Headphones, saw blades, coat hangers: how human trash in Australian bird nests changed over 195 years


This, if you can believe it, is part of a magpie nest.
Kathy Townsend, Author provided

Kathy Ann Townsend, University of the Sunshine Coast and Dominique Potvin, University of the Sunshine CoastEnvironmental scientists see flora, fauna and phenomena the rest of us rarely do. In this series, we’ve invited them to share their unique photos from the field.


When we opened a box supplied by museum curators, our research team audibly gasped. Inside was a huge Australian magpie nest from 2018.

It was more than a metre wide and made up of the strangest assortment of items, including wire coat hangers, headphones, saw blades and plastic 3D glasses — a mix of detritus reflecting our modern lifestyle.

This was one of almost 900 Australian nest specimens dating back over 195 years that we inspected for our recent, world-first study.

We estimate that today, around 30% of Australian bird nests incorporate human-made materials (primarily plastics). We also noted a steady increase in nest parasites over this period.

It’s clear the types of debris the birds use has reflected changes in society over time. They highlight the unexpected and far-reaching ways Australians impact their environment, and put birds in danger.

The full magpie nest from 2018 that was collected outside a construction site.
Kathy Townsend, Author provided

The first synthetic item

Birds and humans have been sharing spaces and habitats throughout history.

It’s well known birds incorporate material from their environment into their nests, making them ideal indicators of environmental changes and human activity. It’s also well known, particularly among scientists, that museum collections can provide unique insight into environmental changes through time and space.

Compare the magpie nest above to this natural butcherbird nest from 1894. Butcherbirds are in the same family as magpies.
Dominique Potvin, Author provided

With this in mind, our international team investigated Australian museum bird nest specimens collected between 1823 and 2018. Sourced from Museums Victoria and CSIRO’s Crace Site in Canberra, we inspected a total of 892 nests from 224 different bird species.

Australian birds generate an amazing array of nest types. Rufous fantails, for example, build delicately woven structures made of fine grass and spiderwebs, while welcome swallows and white-winged choughs create nests out of mud, which dry incredibly hard and can be used year after year.

A woven egg cup nest from 1870, made of grass and spiderwebs, by the rufous fantail.
Kathy Townsend, Author provided
Fabiola Opitz, a member of our research team, measuring mudnest collected circ. 1933 of a whitewinged chough. These mudnests can last for years.
Dominique Potvin, Author provided

Before the 1950s, human-made debris found in the nests consisted of degradable items such as cotton thread and paper.

This changed in 1956, when we found the first synthetic item in a bird nest from Melbourne: a piece of polyester string. This appearance correlates with the increased availability of plastic polymers across Australian society, seven years after the end of the second world war.

Australian magpies earn their name

We also determined, based on collection date and using historical maps, whether the nests came from natural, rural or urban landscapes. And it turns out the nest’s location, when it was built, and the species that made it largely determined whether human-made materials were present.

Brown nest with blue string
The nest of a noisy miner found on the Sunshine Coast, Queensland, in 2020 with plastic string.
Kathy Townsend, Author provided

Our study found nests built close to urban areas or farmland after the 1950s by birds from the families Craticidae (Australian magpies and butcherbirds), Passeridae (old world or “true” sparrows) and Pycnonotidae (bulbuls) had significantly more human-made debris.

Familiar to many an urban bird enthusiast, these species tend to adapt quickly to new environments. The incorporation of human materials in nests is likely one example of this behavioural flexibility.

The research team also had access to ten bowerbird bowers from the family Ptilonorhynchidae, spanning more than 100 years. Male bowerbirds are known for creating elaborate structures, decorated with a range of colourful items to attract a mate.

A silvereye or gerygong nest from 2019.
Kathy Townsend, Author provided

In the 1890s, the birds decorated their bowers with natural items such as flowers and berries. Newspaper scraps were the only human-produced items we identified.

This changed dramatically 100 years later, where the most sought-after items included brightly coloured plastics, such as straws, pen lids and bottle caps.

A satin bowerbird collecting blue junk. Video: BBC Wildlife.

But there are tragic consequences

When birds weave non-biodegradable materials — such as fishing line and polymer rope — into their nests, it increases the risk of entanglement, amputation and even accumulation of plastics in the gut of nestlings.

For example, we found evidence of one pallid cuckoo juvenile dying in 1981 after it was entangled in plastic twine used by its adoptive bell miner parents.

This is the bell miner nest with twine that caused the cuckoo chick to die, according to the museum notes.
Dominique Potvin, Author provided

Plastic was not the only issue. We found the prevalence of nest parasites that attack the young chicks also increased by about 25% over the last 195 years.

Nest parasites can kill huge numbers of nestlings. Recent research into the forty-spotted pardalote in Tasmania, a threatened species, has shown nest parasites kill up to 81% of its nestlings.

What has caused this increase isn’t clear. However, the team determined it wasn’t directly linked to urban or rural habitat type, or the presence of human-made materials in the nest. This goes against the findings of other studies, which show a decrease of parasites in nests that incorporated items such as cigarettes.

Interestingly, we did find eucalyptus leaves might deter parasites, as nests that incorporated them were less likely to show evidence of parasitism.

An eastern yellow robin nest from 2003, with eucalyptus leaves, lichen, spider webs and no parasites. Eastern yellow robins are specialist nest builders that don’t tend to stray from using specific natural items.
Kathy Townsend, Author provided
This nest from 1932 is from an Australian magpie, using eucalyptus leaves.
Kathy Townsend, Author provided

It may be, therefore, that sticking with certain natural materials is not only better for the safety of nest inhabitants, but also may have an added effect of pest control.

Stop littering, please

While most are aware of how plastics harm sea life, our study is one of the first to show the impact goes further to harm animals living in our own backyard. If the trend continues, the future for Australian birds looks bleak.

However, we can all do something about it.

A weebill or mistletoe bird’s woven nest from 1941, with tufts of spider webs and plant fluff.
Kathy Townsend, Author provided

It is as simple as being responsible for our rubbish and supporting proposed legislation and campaigns for moving away from single-use plastics.

The team had access to nests from 224 different species, which equates to only about a quarter of Australia’s total of 830 bird species.

There is still plenty more to discover.




Read more:
Birds on beaches are under attack from dogs, photographers and four-wheel drives. Here’s how you can help them


The Conversation


Kathy Ann Townsend, Senior Lecturer in Animal Ecology, University of the Sunshine Coast and Dominique Potvin, Lecturer in Animal Ecology, University of the Sunshine Coast

This article is republished from The Conversation under a Creative Commons license. Read the original article.

A lone tree makes it easier for birds and bees to navigate farmland, like a stepping stone between habitats


Shutterstock

Carla Archibald, Deakin University; Eduardo van den Berg, Federal University of Lavras, and Jonathan Rhodes, The University of QueenslandVast, treeless paddocks and fields can be dangerous for wildlife, who encounter them as “roadblocks” between natural areas nearby. But our new research found even one lone tree in an otherwise empty paddock can make a huge difference to an animal’s movement.

We focused on the Atlantic Forest in Brazil, a biodiversity hotspot with 1,361 different known species of wildlife, such as jaguars, sloths, tamarins and toucans. Habitat loss from expanding and intensifying farmland, however, increasingly threatens the forest’s rich diversity of species and ecosystems.

We researched the value of paddock trees and hedges for birds and bees, and found small habitat features like these can double how easily they find their way through farmland.

This is important because enabling wildlife to journey across farmlands not only benefits the conservation of species, but also people. It means bees can improve crop pollination, and seed-dispersing birds can help restore ecosystems.

Connecting habitats

Lone trees in paddocks, hedges and tree-lined fences are common features of farmlands across the world, from Brazil to Australia.

They may be few and far between, but this scattered vegetation makes important areas of refuge for birds and bees, acting like roads or stepping stones to larger natural habitats nearby.

Scattered paddock trees, for instance, offer shelter, food, and places to land. They’ve also been found to create cooler areas within their canopy and right beneath it, providing some relief on scorching summer days.

Hedges and tree-lined fences are also important, as they provide a safe pathway by providing hiding places from predators.

White-browed meadowlark perched on a bush in a farm paddock within the Atlantic Forest
White-browed meadowlark perched on a bush in a farm paddock within the Atlantic Forest.
Milton Andrade Jr, CC BY

For our research, we used satellite images of the Atlantic Forest and randomly selected 20 landscapes containing different amounts of forest cover.

We then used mathematical models to calculate the habitat connectivity of these landscapes for three groups of species — bees, small birds such as the rufous-bellied thrush, and large birds such as toucans — based on how far they can travel.




Read more:
Urban golf courses are biodiversity oases. Opening them up puts that at risk


And we found in areas with low forest cover, wildlife is twice as likely to move from one natural habitat to another if paddock trees and hedges can be used as stepping stones.

We also found vegetation around creeks and waterways are the most prevalent and important type of on-farm habitat for wildlife movement. In Brazil, there are legal protections for these areas preventing them from being cleared, which means vegetation along waterways has become relatively common compared to lone trees and hedges, in places with lower forest cover.

Insights for Australia

While the contribution of lone trees, hedges and tree-lined fences towards conservation targets is relatively low, our research shows they’re still important. And we can apply this knowledge more widely.

Two koalas sitting on a branch
Koalas use roadside vegetation for feeding and resting.
Shutterstock

For example, in Australia, many koala populations depend on scattered trees for movement and habitat. In 2018, CSIRO researchers in Queensland tracked koalas using GPS, and found koalas used roadside vegetation and scattered trees for feeding and resting significantly more than they expected.

Likewise, lone trees, hedges and tree-lined fences can also facilitate the movement of Australian fruit-eating birds such as the olive-backed oriole and the rose-crowned fruit dove. Improving habitat connectivity can help these birds travel across landscapes, feeding and dispersing seeds as they go.

In fragmented landscapes, where larger patches of vegetation are hard to find, dispersing the seeds of native plants encourages natural regeneration of ecosystems. This is a key strategy to help achieve environmental restoration and conservation targets.

Policies overlook lone trees

In Brazil, there’s a strong initiative to restore natural areas, known as the Brazilian Pact for Restoration. This pact is a commitment from non-government organisations, government, companies and research centres to restore 15 million hectares of native vegetation by 2050.

However, the pact doesn’t recognise the value of lone trees, hedges and tree-lined fences.




Read more:
Stopping koala extinction is agonisingly simple. But here’s why I’m not optimistic


Likewise, the Brazilian Forest Code has historically provided strong legal protection for forests since it was introduced. While this policy does value vegetation along waterways, it overlooks the value of lone trees, hedges or tree-lined fences.

These oversights could result in poor connectivity between natural areas, seriously hampering conservation efforts.

Australia doesn’t fare much better. For example, in Queensland, the native vegetation management laws protect only intact native vegetation or vegetation of a certain age. This means scattered, but vital, vegetation isn’t protected from land clearing.

Small habitat features scattered across a farm paddock in the Atlantic Forest.
Flávia Freire Siqueira, CC BY., Author provided

Helping your local wildlife

But farmers and other landowners in Australia can make a big difference through land stewardship grant schemes (such as from Landcare) and private land conservation programs (such as Land for Wildlife or conservation covenants).

These schemes and programs can help landowners finance revegetation and protect native vegetation. Grants and programs vary by state and territory, and local council.




Read more:
Backyard gardeners around the world are helping to save Australia’s deeply ancient Wollemi pine


Restoring natural areas is a key goal on the global conservation agenda for the next decade, and it’s clear that lone trees, hedges and tree-lined fences on farms may play a larger role than once thought.

So think twice before you remove a tree or a hedge. It might be a crucial stepping stone for your local birds and bees.


The authors gratefully acknowledge the contributions of Dr Flávia Freire Siqueira who led this research collaboration, and co-authours Dr Dulcineia de Carvalho and Dr Vanessa Leite Rezende from the Federal University of Lavras.The Conversation

Carla Archibald, Research Fellow, Conservation Science, Deakin University; Eduardo van den Berg, , Federal University of Lavras, and Jonathan Rhodes, Associate Professor, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Seabirds are today’s canaries in the coal mine – and they’re sending us an urgent message


Shutterstock

David Schoeman, University of the Sunshine Coast; Brian Allan Hoover, Chapman University, and William Sydeman, University of California San DiegoJust as caged canaries once warned coal miners of the risk of carbon monoxide poisoning, free-flying seabirds are now warning humanity about the deteriorating health of our oceans.

Seabirds journey vast distances across Earth’s seascapes to find food and to breed. This exposes them to changes in ocean conditions, climate and food webs. This means their biology, particularly their breeding successes, can reveal these changes to us on a rare, planet-wide scale.

We collated and analysed the world’s largest database on seabird breeding. Our findings reveal a key message: urgency in the Northern Hemisphere and opportunity in the south.

The Northern Hemisphere ocean systems are degraded and urgently need better management and restoration. Damage to Southern Hemisphere oceans from threats such as climate change and industrial fishing is accelerating, but opportunities remain there to avoid the worst.

northern gannet pair with offspring
Seabird breeding success is a good indicator of ocean health.
Shutterstock

Oceans at a crossroads

Seabirds often travel far across the planet. For example, many sooty shearwaters breed in New Zealand, yet travel each year to the productive waters of the northeast Pacific. Arctic terns migrate even further, travelling each year between the Arctic and Antarctic.

Scientists often use satellite-derived data sets to determine, for example, how the oceans’ surfaces are warming or how ocean food webs are changing. Few such data sets span the globe, however, and this is where seabirds come in.

Over its long journey, a seabird eats fish and plankton. In doing so, it absorbs signals about ocean conditions, including the effects of pollution, marine heatwaves, ocean warming and other ecological changes.

Seabird breeding productivity (the number of chicks produced per female per year) depends on the food resources available. In this way, seabirds are sentinels of change in marine ecosystems. They can tell us which parts of oceans are healthy enough to support their breeding and which parts may be in trouble.




Read more:
It might be the world’s biggest ocean, but the mighty Pacific is in peril


Shearwater floats on water
Many sooty shearwaters breed in New Zealand then migrate to the northeast Pacific.
Shutterstock

Deciphering seabird messages

In some cases, seabirds tell us directly about major distress in the oceans. This was the case in 2015-16, when around a million emaciated common murres died, many washing up on beaches from California to Alaska. The seabirds experienced severe food shortages caused by an acute marine heatwave.

In other cases, seabird health can hint at longer-term and more subtle disruption of ocean ecosystems, and we are left to decipher these messages.

In this task, seabird breeding provides important clues about marine food webs that are otherwise difficult or impossible to measure directly, especially at global scales. Thankfully, seabird scientists around the world have consistently measured breeding productivity over decades.

Our research team included 36 of these scientists. We collated a database of breeding productivity for 66 seabird species from 46 sites around the world, from 1964 to 2018. We used the data to determine whether seabirds were producing relatively more or fewer chicks over the past 50 years, and whether the risk of breeding failure was increasing or decreasing.

bird flies over water
In the Southern Hemisphere, there’s still time to reverse the oceans’ plight.
Shutterstock

Striking findings

In the Northern Hemisphere, breeding productivity of plankton-eating birds such as storm petrels and auklets increased strongly over 50 years, but breeding productivity of fish-eating birds declined sharply.

In the Southern Hemisphere, by contrast, breeding productivity of plankton-eating seabirds declined weakly, but increased strongly for fish eaters.

In short, fish-eating seabirds in the north are in trouble. Decreasing breeding productivity leads to population declines, and the low breeding rate of seabirds (many species only have one chick per year) means populations recover slowly.

More worrying, though, were our findings on the risk of breeding failure.

In the Southern Hemisphere, the probability of breeding failure was low throughout the study period. The same was true for Northern Hemisphere plankton feeders. But fish eaters in the north showed dramatically increasing risk of breeding failure, most acutely in the years since 2000.

Importantly, increasing risk of breeding failure was also much higher for seabirds that feed at the ocean’s surface, such as black-legged kittiwakes, compared with those that feed at greater depths, such as puffins.




Read more:
Birds on beaches are under attack from dogs, photographers and four-wheel drives. Here’s how you can help them


Risk of breeding failure was higher for seabirds that feed at the ocean’s surface.
©Eric J Woehler

What this tells us

Unfortunately, these results match what we know about human-caused damage to the ocean.

First, many pollutants such as plastics collect close to the ocean surface. They are often eaten by surface-feeding seabirds, potentially hampering their ability to produce chicks.

Similarly, the rate of ocean warming has been more than three times faster, and the change in number of marine heatwave days twice as large, on average, in the Northern than Southern Hemisphere over the past 50 years.

Likewise, northern oceans have sustained industrial fisheries for far longer than those in the south. This has likely reduced food supplies to Northern Hemisphere fish-eating seabirds over longer periods, causing chronic disruptions in their breeding success.

But human impacts in the Southern Hemisphere are accelerating. Ocean warming and marine heatwaves are becoming more intense, and industrial fisheries and plastic pollution are ever-more pervasive.

Rate of warming of the surface ocean over the past 50 years.

We must heed the warnings from our seabird “canaries”. With careful planning and marine reserves that take account of projected climate change, the Southern Hemisphere might avoid the worst consequences of human activity. But without action, some seabird species may be lost and ocean food webs damaged.

In the Northern Hemisphere, there is no time to waste. Innovative management and restoration plans are urgently needed to avoid further deterioration in ocean health.

This story is part of Oceans 21

Watch for new articles ahead of the COP26 climate conference in Glasgow in November. Brought to you by The Conversation’s international network.The Conversation

David Schoeman, Professor of Global-Change Ecology, University of the Sunshine Coast; Brian Allan Hoover, Postdoctoral Fellow, Chapman University, and William Sydeman, Adjunct associate, University of California San Diego

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Mouse plague: bromadiolone will obliterate mice, but it’ll poison eagles, snakes and owls, too


Masked owl (Tyto novaehollandiae), one of many birds of prey at great risk of secondary poisoning
Belinda Davis, Author provided

Robert Davis, Edith Cowan University; Bill Bateman, Curtin University; Damian Lettoof, Curtin University; Maggie J. Watson, Charles Sturt University, and Michael Lohr, Edith Cowan UniversityIt’s the smell that hits you first. The scent of urine and decomposing bodies. Then you notice other signs: scuttles and squeaks, small dead bodies leaking blood, tails sticking out of hubcaps.

If you’ve lived through a mouse plague, you’ve seen this, and smelled the stench of mice dying of poison baits.

As a desperate measure to help combat the mouse plague devastating rural communities across New South Wales, the state government yesterday secured 5,000 litres of bromadiolone. This is a bait that’s usually illegal to roll out at the proposed scale.

This is a bad idea. While bromadiolone effectively kills mice, it also travels up the food chain to poison predators who eat the mice, and other species. And these predators, from wedge-tailed eagles to goannas, are coming out in droves to feast on their abundant prey.

When your prey is everywhere

Animal plagues in Australia are fuelled by the “boom and bust” of rainfall.

We have natural, flood-driven population explosions of the native long-haired rat, with accompanying booms of letter-winged kites, their predator. We also have locust plagues when the conditions are right, leading to antechinus or mice plagues which eat the locusts.

Since at least the late 1800s, we’ve had terrible plagues of the introduced house mouse (Mus musculus). But rarely has it been this bad, with conditions currently seeming worse than the last plague in 2011, which caused over A$200 million in crop damage alone.

High numbers of birds of prey — nankeen kestrels, black-shouldered kites and barn owls — are often reported feasting on plague mice.

Snakes, goannas, native carnivores such as quolls, and feral cats and foxes, also take advantage of the abundant food. Pets, especially cats and some dogs, are highly likely to consume mice under these conditions, too.

Poisoning the food web

Laying out poison baits is one way people try to end mouse infestations and plagues. So-called “anticoagulant rodenticides” are divided into first and second generations, based on when they were first synthesised and the differences in potency.

Wedge-tailed eagle
Wedge-tailed eagles are among the predators that take advantage of the house mouse plague.
Shutterstock

Second generation anticoagulant rodenticides have higher toxicities than first generation, and are lethal after a single feed. First generation rodenticides, on the other hand, require rodents to feed on them for consecutive days to be lethal.

But mouse-eating predators are highly exposed to second generation rodenticides. For most animal species, the lethal doses of rodenticide aren’t yet known.

A scientific review from 2018 documented the poisoning of 31 bird, five mammal and one reptile species. Second generation aniticoaugulant rodenticides were implicated in the death of these animals.

Our research from 2020 found urban reptiles are highly exposed to second generation rodenticides, too. This includes mouse-eating snakes, called dugites, which had up to five different rodent poisons in them.

We also found poisons in frog-eating tiger snakes, and in omnivorous bobtail skinks which eat fruit, vegetation and snails. This is even more concerning because it shows how second generation rodenticides can saturate the entire foodweb, affecting everything from slugs to fish.

Bobtail skink
Bobtail skinks don’t eat poisoned mice, but they’ve still been found with poison in their systems.
Shutterstock

Bromadiolone is particularly dangerous, even to humans

The NSW government secured bromadiolone baits as part of its $50 million mouse plague support package for regional communities.

Five thousand litres of the poison can treat around 95 tonnes of grain, and the government will provide it for free to primary producers once federal authorities approve its use.

Bromadiolone is usually restricted to use in and around buildings. But given the widespread impacts on wildlife, using bromadiolone at the proposed scale will do more harm than good.

Past research on bromadiolone has shown residues persist for up to 135 days in the carcasses of voles (another rodent species). In international studies, bromadiolone has been found in the livers of a host of birds of prey, including a range of owl species, red kites, sparrowhawks and golden eagles.

Flock of chickens
Humans can be exposed, too, by eating the eggs of chickens that ate the mice.
Shutterstock

And it’s not just a problem for wildlife, humans are also at risk of exposure. For example, we can get exposed from eating eggs from chickens that feed on poisoned mice, or more directly from eating other animals that may have ingested poisoned mice.

A 2013 study looked at chicken eggs for human consumption, and detected bromadiolone in eggs between five and 14 days after the chicken ingested the poison. It’s not yet clear how many of these eggs we’d have to eat for us to get sick.

So what are the alternatives?

There are highly effective first generation rodenticides that provide viable solutions for managing mouse plagues. They may take a little longer to kill mice, but the upshot is they don’t stick around in the environment. A 2020 study found house mice in Perth didn’t have genetic resistance to first generation rodenticides, which suggests they’re effectively lethal.

Another approach has been to use zinc phosphide, a poison which is unlikely to secondarily poison other animals that eat the poisoned mice. However, zinc phosphide is still extremely toxic and will kill sheep, cows, pets and even humans if directly eaten.

Rolling out double-strength zinc phosphide may be the lesser of the evils in causing secondary poisoning, but only if used very carefully.

And another way to help control the mouse plague is to limit food resources for mice on farms. Farmers can minimise grain on ground, and Australia should invest in research for grain storage facilities that are less permeable to mice.

Mouse plagues are a regular cycle in Australia. Natural predators not only help create healthy, natural ecosystems, but also they help with mouse control. Second generation rodenticides will only destroy and weaken the predator populations we need to help us combat the next plague.The Conversation

Robert Davis, Senior Lecturer in Wildlife Ecology, Edith Cowan University; Bill Bateman, Associate professor, Curtin University; Damian Lettoof, PhD Candidate, Curtin University; Maggie J. Watson, Lecturer in Ornithology, Ecology, Conservation and Parasitology, Charles Sturt University, and Michael Lohr, Adjunct Lecturer, Edith Cowan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The secret life of puddles: their value to nature is subtle, but hugely important


Shutterstock

Gregory Moore, The University of MelbourneIt’s official: Australians endured the coldest, wettest summer in at least five years thanks to La Niña, a climate phenomenon over the Pacific Ocean.

Before we knew it, autumn rolled in bringing more rain. Tragically, it led to widespread flooding across New South Wales, but elsewhere it helped to create more puddles. In our urban environments puddles are inconvenient: they can damage property and block our paths. But from a biological perspective, puddles are very important components of microhabitats and biodiversity.

We know for many animals — including birds and pets — puddles are a ready source of drinking water and provide a much-needed bath after a hot and dusty day. They’re also well known for providing water-reliant species such as mosquitoes with opportunities for breeding, and many of us may remember watching tadpoles developing in puddles as children.

But puddles make more nuanced and subtle contributions to the natural world than you may have realised. So with more rain soon to arrive, let’s explore why they’re so valuable.

Rainy day on Swanston St, Melbourne
Puddles are getting harder to find in urban environments.
Shutterstock

Take a closer look

Puddles are a diverse lot. They can be small or large, shallow or deep, long lasting or gone in a matter of hours. If you look closely at a puddle you will often find it is not even, especially on a slope.

Puddles consist of small, naturally formed ridges (berms) and depressions (swales). The berms form from silt and organic matter like leaf litter, which act as mini dams holding back the water in the swales behind them.

Berms and swales can be hard to see, but if you look closely they’re everywhere and contribute to the retention of water, affecting the depth, spread and the very existence of the puddle.

All of this means they meet the needs of different species.

Flooded country path
The tiny ridges and depressions in puddles can make a big difference to wildlife.
Shutterstock

On rainy days you may have seen birds such as magpies feeding on worms that wriggle to the surface. Worm burrows can be two to three metres deep and many species might come to the surface to feed on leaf litter.

Worms emerge during and after heavy rain when water floods their burrows and soil becomes saturated. The worms won’t drown but they do need oxygen, which is low in very wet soils.

Often in drier weather, getting a worm is not as easy as you might think — not even for the legendary early bird. So when heavy rain drives worms to the surface, it’s party time for birds that feed on them, and they make the most of the opportunity.

A spotted pardalote near a puddle
A spotted pardalote inspecting puddle.
Shutterstock

Swales in puddles often persist for days, which allows water-dependent insects to breed. Mosquito larvae, for instance, live in water for between four and 14 days, depending on temperature (so if you’re worried about mozzies, then remember puddles have to persist for days before the pesky pests emerge).

Tadpoles take between four and 12 weeks to develop into frogs, and requires a deeper, long-lasting puddle. But these puddles are becoming rarer in urban areas, and so it’s not often you see tadpoles or frogs in our suburbs.

Why seeds love them

Puddles also provide small, but important, reservoirs where seeds of many plant species germinate. In some cases, the seeds have chemical inhibitors in them, which prevent the seeds from germinating until after a period of heavy rainfall.

Then, the inhibitors are leeched from or diluted within the seeds, allowing them to germinate. Many desert species have this adaptation, including Australian eremophilas (emu bush).




Read more:
La Niña will give us a wet summer. That’s great weather for mozzies


In other cases, plants that grow all year round (annoyingly, weeds among them) need the dose of water puddles provide to kick start their very rapid growth and reproduction.

Easily germinated plants (such as tomatoes and cabbages) and ornamental flowering plants (such as hollyhocks and delphiniums) often require just a little extra water to trigger the whole germination process.

Important growing opportunities for iconic trees

Puddles also provide more subtle opportunities for wildlife. Take Australia’s iconic river red gums (Eucalyptus camaldulensis) as an example. River red gums are water-loving trees that can withstand up to nine months of inundation without getting stressed.

River red gum
Puddles can wash away plant-inhibiting chemicals from the soil.
Shutterstock

What’s not so well known, however, is river red gums produce chemicals that rain washes from their leaves, accumulating beneath the tree. These chemicals can inhibit the growth of plants, such as weeds, under the canopies.

This effect — where chemicals produced by one plant have an effect on other plants — is called “allelopathy”. Many wattle species produce allelopathic chemicals and so do some important food plants, such as walnuts, rice and the common pea.

River red gum allelopathic chemicals can prevent the trees’ own seedlings from growing near them. So river red gums require floods to wash the chemicals from the soil away. This mechanism allows river red gums to germinate and regenerate when the soil is wet, and in places away from the competition of mature trees.




Read more:
The river red gum is an icon of the driest continent


Puddles can do the same thing, on a small scale, ensuring trees have plenty of opportunities to persist in the wild. This pattern of regeneration is important to provide a mosaic of species and trees of different ages, making up a diverse range of habitats for other wildlife.

Puddles are no piddling problem

A muddy golden retriever playing in a puddle
Puddles are becoming harder to find in the suburbs.
Shutterstock

As property developers iron the creases from our created landscapes with much less open space and more paved surfaces, puddles are becoming harder to find close to home.

Taking away puddles removes a whole range of microhabitats, jeopardising the chances of a diverse range of species to breed and persist, especially in urban areas. These days, any loss of biodiversity is worrying.

So when you’re next out and about after or during heavy rain, keep an eye out for puddles.

Remember the life that depends on them and, if you can, try not to disturb them. Perhaps capture the joy of jumping over — rather than in — them. They are not just a nuisance, but a key to a nuanced and biodiverse local community.The Conversation

Gregory Moore, Doctor of Botany, The University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Birds on beaches are under attack from dogs, photographers and four-wheel drives. Here’s how you can help them


An adult fairy tern feeding a chick.
Claire Greenwell, Author provided

Claire Greenwell, Murdoch University

Environmental scientists see flora, fauna and phenomena the rest of us rarely do. In this new series, we’ve invited them to share their unique photos from the field.


Each year, oystercatchers, plovers and terns flock to beaches all over Australia’s coastline to lay eggs in a shallow scrape in the sand. They typically nest through spring and summer until the chicks are ready to take flight.

Spring and summer, however, are also when most people visit the beach. And human disturbances have increased breeding failure, contributing to the local contraction and decline of many beach-nesting bird populations.

Take Australian fairy terns (Sternula nereis nereis) in Western Australia, the primary focus of my research and photography, as an example. Their 2020-21 breeding season is coming to an end, and has been relatively poor.

Courting pair of Fairy Terns on the beach
Australian fairy tern pair. Males feed female mates, helping to supplement nutrients and energy for egg production.
Claire Greenwell

Fox predation and flooding from tidal inundation wiped out several colonies. Unfathomably, a colony was also lost after a four-wheel drive performed bog-laps in a sign-posted nesting area. Unleashed dogs chased incubating adults from their nests, and photographers entered restricted access sites and climbed fragile dunes to photograph nesting birds.

These human-related disturbances highlight the need for ongoing education. So let’s take a closer look at the issue, and how communities and individuals can make a big difference.

Nesting on the open beach

Beach-nesting birds typically breed, feed and rest in coastal habitats all year round. During the breeding season, which varies between species, they establish their nests above the high-water mark (high tide), just 20 to 30 millimetres deep in the sand.

Fairy Tern sitting on eggs
Eggs are sandy coloured and have a mottled appearance, which help them to blend in with the environment.
Claire Greenwell
Two Fairy Tern chicks. Down feathers are lightly coloured and mottled to help increase camouflage.
Fairy tern chicks crouch close to the ground to hide from predatory birds. Down feathers are lightly coloured and mottled to help increase camouflage.
Claire Greenwell

Some species, such as the fairy tern, incorporate beach shells, small stones and organic material like seaweed in and around the nest to help camouflage their eggs and chicks so predators, such as gulls and ravens, don’t detect them easily.

An adult Fairy Tern moving shell material around the nest site to increase camouflage of the eggs.
An adult fairy tern moving shell material around the nest site to increase the camouflage of its eggs.
Claire Greenwell

While nests are exposed and vulnerable on the open beach, it allows the birds to spot predators early and to remain close to productive foraging areas.

Still, beach-nesting birds live a harsh lifestyle. Breeding efforts are often characterised by low reproductive success and multiple nesting attempts may be undertaken each season.

Eggs and chicks remain vulnerable until chicks can fly. This takes around 43 days for fairy terns and about 63 days for hooded plovers (Thinornis rubricollis rubricollis).

Adult Fairy Tern feeding a chick
Eggs and chicks are vulnerable until chicks are capable of flight.
Claire Greenwell

Disturbances: one of their biggest threats

Many historically important sites are now so heavily disturbed they’re unable to support a successful breeding attempt. This includes the Leschenault Inlet in Bunbury, Western Australia, where fairy tern colonies regularly fail from disturbance and destruction by four-wheel drives.

Species like the eastern hooded plover and fairy tern have declined so much they’re now listed as “vulnerable” under national environment law. It lists human disturbance as a key threatening process.




Read more:
One cat, one year, 110 native animals: lock up your pet, it’s a killing machine


Birds see people and dogs as predators. When they approach, nesting adult birds distance themselves from the nest and chicks. For example, terns typically take flight, while plovers run ahead of the threat, “leading” it away from the area.

When eggs and chicks are left unattended, they’re vulnerable to predation by other birds, they can suffer thermal stress (overheating or cooling) or be trampled as their cryptic colouration makes them difficult to spot.

Silver Gull carrying away a Fairy Tern chick
Natural predators such as silver gulls readily take eggs and chicks when left unattended.
Claire Greenwell

Unlike plovers and oystercatchers, fairy terns nest in groups, or “colonies”, which may contain up to several hundred breeding pairs. Breeding in colonies has its advantages. For example, collective group defence behaviour can drive off predatory birds such as silver gulls (Chroicocephalus novaehollandiae).

However, this breeding strategy can also result in mass nesting failure. For example, in 2018, a cat visiting a colony at night in Mandurah, about 70 km south of Perth, killed six adults, at least 40 chicks and led to 220 adult birds abandoning the site. In other instances, entire colonies have been lost during storm surges.

Adult Fairy Terns mobbing a juvenile Crested Tern
Adult fairy terns engaged in group defence or ‘mobbing’ to drive away a juvenile crested tern from a colony.
Claire Greenwell

Small changes can make a big difference

Land and wildlife managers are becoming increasingly aware of fairy terns and the threats they face. Proactive and adaptive management combined with a good understanding of early breeding behaviour is helping to improve outcomes for these vulnerable birds.

Point Walter, in Bicton, WA, provides an excellent example of how recreational users and beach-nesting birds can coexist.

Point Walter, 18 km from Perth city, is a popular spot for picnicking, fishing, kite surfing, boating and kayaking. It’s also an important site for coastal birds, including three beach-nesting species: fairy terns, red-capped plovers and Australian pied oystercatchers (Haematopus longirostris).

Point Walter, Bicton with kite surfers and kayakers
Point Walter is a popular recreational site in Perth. Recent effective management, including seasonal closures, have enabled fairy terns, red-capped plovers and Australian pied oystercatchers to nest at the end of the sand bar.
Claire Greenwell

The end of the sand bar is fenced off seasonally, and as a result the past six years has seen the number of terns increase steadily. For the 2020-2021 season, the sand bar supported at least 150 pairs.

The closure also benefits the local population of red-capped plovers and Australian pied oystercatchers, who nest at the site each year.

Fairy Tern chick being brooded by its parent.
Fairy tern brooding (sitting on) its chick.
Claire Greenwell
An adult Australian Pied Oystercatcher teaching its offspring to hunt for prey.
An adult Australian pied oystercatcher teaching its offspring to hunt for prey.
Claire Greenwell

What’s more, strong community stewardship and management interventions by the City of Mandurah to protect a fairy tern colony meant this season saw the most successful breeding event in more than a decade — around 110 pairs at its peak.

Interventions included temporary fencing, signs, community education and increased ranger patrols. Several pairs of red-capped plovers also managed to raise chicks, adding to the success.

These examples highlight the potential for positive outcomes across their breeding range. But intervention during the early colony formation stage is critical. Temporary fencing, signage and community support are some of our most important tools to protect tern colonies.

So what can you do to protect beach-nesting birds?

Fairy Tern chick
A fairy tern chick at a site dedicated to fairy tern breeding.
Claire Greenwell
  • share the space and be respectful of signage and fencing. These temporary measures help protect birds and increase their chance of breeding success

  • keep dogs leashed and away from known feeding and breeding areas

  • avoid driving four-wheel drive vehicles on the beach, particularly at high tide

  • keep cats indoors or in a cat run (enclosure)

  • if you see a bird nesting on the beach, report it to local authorities and maintain your distance

  • avoid walking through flocks of birds or causing them to take flight. Disturbance burns energy, which could have implications for breeding and migration.




Read more:
Don’t let them out: 15 ways to keep your indoor cat happy


The Conversation


Claire Greenwell, PhD Candidate, Murdoch University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Birds that play with others have the biggest brains – and the same may go for humans



Shutterstock

Gisela Kaplan, University of New England

Have you ever seen magpies play-fighting with one another, or rolling around in high spirits? Or an apostlebird running at full speed with a stick in its beak, chased by a troop of other apostlebirds? Well, such play behaviour may be associated with a larger brain and a longer life.

For the past 50 years, international animal cognition research has often related the use of tools such as rocks and sticks to cognitive abilities in animals. But my research on Australian native birds, published in Scientific Reports, casts doubt on long-held assumptions about the links between large brains and tool use.

My study found no significant association between tool use and brain mass. However, very clear differences in relative brain mass emerged when birds showing play behaviour were compared to those that didn’t play. In particular, birds that played with others (known as social play) had the largest brain mass, relative to body size, and even the longest lifespans.

The results suggest play behaviour may be an important driver in the evolution of large brains in a number of species, including humans.

Magpie engaged in play
Magpies engaged in complex social play. One magpie hung solo from a towel on a washing line then was joined by others. One newcomer pulled the hanging magpie’s foot to make it swing, and the other gave it a push back the other way, and so on.
The Magpie Whisperer

Tool use in birds

Tool use has been studied in a wider range of species than play behaviour. Some internationally famous Australian examples include:

  • the black-breasted buzzard releasing rocks from their beaks to crack emu eggs

  • the black kite picking up burning embers and twigs and dropping them on dry grass areas to start a fire. The bird then feasts on fleeing or injured insects and vertebrates

  • palm cockatoos that drum with a stick.

According to a classic theory known as the “technical intelligence hypothesis”, humans and other animals developed large brains because circumstances forced them into ever more sophisticated tool use.




Read more:
Bird-brained and brilliant: Australia’s avians are smarter than you think


Palm cockatoos drum with a stick.

So what is bird play?

Play behaviour usually occurs in juveniles but in some species, such as little corellas or galahs, it extends into adulthood. Play behaviour occurs in species which tend to have long juvenile periods, long-term support from parents and which grow up in stable social groups.

Play behaviour is usually subdivided into three categories: solo play, object play and social play.

Solo play: this may involve a single bird running, skipping, jumping, ducking, rolling, hanging, swinging, dancing, sliding and snow-romping. Solo play is the most widespread form of play, common among honeyeaters, parrots, magpies, currawongs, butcherbirds, riflebirds and some pigeon species.

The best acrobat among the pigeons is probably the topknot pigeon, but rainbow lorikeets are also known to love swinging.

Object play: this involves objects of any kind, including sticks, stones and small household items. Object players might carry a stick or stone or even just a leaf around, drop it, then pick it up again and run with it.

Object players are not as numerous as solo players but still widespread across species. Click here to read a lovely description of a kookaburra absorbed in playing with a stone.

Social play: involves two or more individuals. Social play is so far the rarest category. It might involve one bird holding an object in its beak and the others chasing it. Published cases are largely limited to parrots and corvids, and are known in magpies and ravens.




Read more:
What Australian birds can teach us about choosing a partner and making it last


White-winged choughs are known to play a game in which two youngsters simultaneously grab a small stick or a bunch of grass, then each tries to wrest it from the other.

It’s important to note that social players are also solo and object players, but solo or object players may not be social players. The latter is considered a more complex form of play.

It turns out these categories are meaningful when used to analyse a potential link to brain mass. Information on brain weight/mass in Australian birds has been available only since an important study in 2014. It identified brain volumes and body sizes of all Australian bird species, enabling researchers to link these biological data to behavioural data.

A little corella holding onto a wire by the beak and trying to swing.
A little corella performing a daredevil solo stunt — holding onto a wire by the beak and trying to swing.
Gisela Kaplan

A surprising link

My study involved 77 native Australian bird species for which full data sets were available. The results were more than surprising. In the samples used, tool use seems to confer no advantage whatsoever in terms of brain size or life expectancy: no matter whether a species showed tool using or not, relative brain masses were not different. However the results showed, rather dramatically, that brain size and forms of play are associated.

Social players, versus other players and versus non-players showed significantly different average brain sizes in each category:

  • non players have the lowest average brain size

  • solo players had slightly larger brains than non-players

  • object players had larger brains again

  • social players had by far the largest average brain size relative to body weight.

These results are by no means confined to parrots, but are found in songbirds and other orders. Whether this holds for birds globally is not yet known. However, since parrots and songbirds first evolved in Australia, then spread to the rest of the world, the results may indeed hold for birds outside Australia. More research will be needed.




Read more:
Magpies can form friendships with people – here’s how


Which came first – play resulting in large brains or large brains triggering play behaviour – is not known. But whichever way one looks at it, playing socially or even just playing at all, is related to a bigger brain and a long life.

So what does all this mean for human brain evolution? It may be a long shot, but the stages of development in humans and birds seem to have some similarities and this may be significant.

Offspring in humans, as in great apes and other primates, also develop slowly, have protracted childhoods and play extensively as do a surprising number of Australian native birds. It may mean playing together offers more than just passing the time. It could be an evolutionary driver for intelligence, and even for a long life.The Conversation

Gisela Kaplan, Emeritus Professor in Animal Behaviour, University of New England

This article is republished from The Conversation under a Creative Commons license. Read the original article.

These are the plastic items that most kill whales, dolphins, turtles and seabirds



Shutterstock

Lauren Roman, CSIRO; Britta Denise Hardesty, CSIRO; Chris Wilcox, CSIRO, and Qamar Schuyler, CSIRO

How do we save whales and other marine animals from plastic in the ocean? Our new review shows reducing plastic pollution can prevent the deaths of beloved marine species. Over 700 marine species, including half of the world’s cetaceans (such as whales and dolphins), all of its sea turtles and a third of its seabirds, are known to ingest plastic.

When animals eat plastic, it can block their digestive system, causing a long, slow death from starvation. Sharp pieces of plastic can also pierce the gut wall, causing infection and sometimes death. As little as one piece of ingested plastic can kill an animal.

About eight million tonnes of plastic enters the ocean each year, so solving the problem may seem overwhelming. How do we reduce harm to whales and other marine animals from that much plastic?

Like a hospital overwhelmed with patients, we triage. By identifying the items that are deadly to the most vulnerable species, we can apply solutions that target these most deadly items.

Some plastics are deadlier than others

In 2016, experts identified four main items they considered to be most deadly to wildlife: fishing debris, plastic bags, balloons and plastic utensils.

We tested these expert predictions by assessing data from 76 published research papers incorporating 1,328 marine animals (132 cetaceans, 20 seals and sea lions, 515 sea turtles and 658 seabirds) from 80 species.

We examined which items caused the greatest number of deaths in each group, and also the “lethality” of each item (how many deaths per interaction). We found the experts got it right for three of four items.

Plastic bag floats in the ocean.
Film plastics cause the most deaths in cetaceans and sea turtles.
Shutterstock

Flexible plastics, such as plastic sheets, bags and packaging, can cause gut blockage and were responsible for the greatest number of deaths over all animal groups. These film plastics caused the most deaths in cetaceans and sea turtles. Fishing debris, such as nets, lines and tackle, caused fatalities in larger animals, particularly seals and sea lions.

Turtles and whales that eat debris can have difficulty swimming, which may increase the risk of being struck by ships or boats. In contrast, seals and sea lions don’t eat much plastic, but can die from eating fishing debris.

Balloons, ropes and rubber, meanwhile, were deadly for smaller fauna. And hard plastics caused the most deaths among seabirds. Rubber, fishing debris, metal and latex (including balloons) were the most lethal for birds, with the highest chance of causing death per recorded ingestion.




Read more:
We estimate up to 14 million tonnes of microplastics lie on the seafloor. It’s worse than we thought


What’s the solution?

The most cost-efficient way to reduce marine megafauna deaths from plastic ingestion is to target the most lethal items and prioritise their reduction in the environment.

Targeting big plastic items is also smart, as they can break down into smaller pieces. Small debris fragments such as microplastics and fibres are a lower management priority, as they cause significantly fewer deaths to megafauna and are more difficult to manage.

Image of dead bird and gloved hand containing small plastics.
Plastic found in the stomach of a fairy prion.
Photo supplied by Lauren Roman

Flexible film-like plastics, including plastic bags and packaging, rank among the ten most common items in marine debris surveys globally. Plastic bag bans and fees for bags have already been shown to reduce bags littered into the environment. Improving local disposal and engineering solutions to enable recycling and improve the life span of plastics may also help reduce littering.

Lost fishing gear is particularly lethal. Fisheries have high gear loss rates: 5.7% of all nets and 29% of all lines are lost annually in commercial fisheries. The introduction of minimum standards of loss-resistant or higher quality gear can reduce loss.




Read more:
How to get abandoned, lost and discarded ‘ghost’ fishing gear out of the ocean


Other steps can help, too, including

  • incentivising gear repairs and port disposal of damaged nets

  • penalising or prohibiting high-risk fishing activities where snags or gear loss are likely

  • and enforcing penalties associated with dumping.

Outreach and education to recreational fishers to highlight the harmful effects of fishing gear could also have benefit.

Balloons, latex and rubber are rare in the marine environment, but are disproportionately lethal, particularly to sea turtles and seabirds. Preventing intentional balloon releases and accidental release during events and celebrations would require legislation and a shift in public will.

The combination of policy change with behaviour change campaigns are known to be the most effective at reducing coastal litter across Australia.

Reducing film-like plastics, fishing debris and latex/balloons entering the environment would likely have the best outcome in directly reducing mortality of marine megafauna.




Read more:
Newly hatched Florida sea turtles are consuming dangerous quantities of floating plastic


The Conversation


Lauren Roman, Postdoctoral Researcher, Oceans and Atmosphere, CSIRO; Britta Denise Hardesty, Principal Research Scientist, Oceans and Atmosphere Flagship, CSIRO; Chris Wilcox, Senior Principal Research Scientist, CSIRO, and Qamar Schuyler, Research Scientist, Oceans and Atmospheres, CSIRO

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Scientists at work: Sloshing through marshes to see how birds survive hurricanes



A clapper rail with a fiddler crab in its bill.
Michael Gray, CC BY-ND

Scott Rush, Mississippi State University and Mark Woodrey, Mississippi State University

When storms like Huricane Zeta menace the Gulf Coast, residents know the drill: Board up windows, clear storm drains, gas up the car and stock up on water, batteries and canned goods.

But how does wildlife ride out a hurricane? Animals that live along coastlines have evolved to deal with a world where conditions can change radically. This year, however, the places they inhabit have borne the brunt of 10 named storms, some just a few weeks apart.

As wildlife ecologists, we are interested in how species respond to stresses in their environment. We are currently studying how marsh birds such as clapper rails (Rallus crepitans) have adapted to tropical storms along the Alabama and Mississippi Gulf coast. Understanding how they do this entails wading into marshes and thinking like a small, secretive bird.

Least bittern in marsh grass
A least bittern, one of the smallest species of heron.
Michael Gray, CC BY-ND

Mucky and full of life

Coastal wetlands are critically important ecosystems. They harbor fish, shellfish and wading birds, filter water as it flows through and buffer coastlines against flooding.

You wouldn’t choose a Gulf Coast salt marsh for a casual stroll. There are sharp-pointed plants, such as black needlerush​, and sucking mud. In summer and early fall the marshes are oppressively hot and humid. Bacteria and fungi in the mud break down dead material, generating sulfurous-smelling gases. But once you get used to the conditions, you realize how productive these places are, with a myriad of organisms moving about.

Marsh birds are adept at hiding in dense grasses, so it’s more common to hear them than to see them. That’s why we use a process known as a callback survey to monitor for them.

First we play a prerecorded set of calls to elicit responses from birds in the marsh. Then we determine where we think the birds are calling from and visually estimate the distance from the observer to that spot, often using tools such as laser range finders. We also note the type of ecosystem where we detect the birds – for example, whether they’re in a tidal marsh with emergent vegetation or out in the open on mud flats.

Adult clapper rail calling.

Through this process we’ve been able to estimate the distributions of several species in tidal marshes, including clapper rails, least bitterns (Ixobrychus exilis) and seaside sparrows (Ammospiza maritima). We’ve also plotted trends in their abundance and identified how their numbers can change with characteristics of the marsh.

We’ve walked hundreds of miles through marshes to locate nests and to record data such as nest height, density of surrounding vegetation and proximity to standing water, which provides increased foraging opportunities for rails. Then we revisit the nests to document whether they produce young that hatch and eventually leave. Success isn’t guaranteed: Predators may eat the eggs, or flooding could wash them out of the nest and kill the developing embryos inside.

Salt marshes shelter many types of plants, birds, animals, fish and shellfish.

Rails in the grass

Our research currently focuses on clapper rails, which look like slender chickens with grayish-brown feathers and short tails. Like many other marsh birds, they have longish legs and toes for walking across soft mud, and long bills for probing the marsh surface in search of food. They are found year-round along the Atlantic and Gulf coasts.

Clapper rails typically live in tidal marshes where there is vegetation to hide in and plenty of fiddler crabs, among their frequent foods. Because they are generally common and rely on coastal marshes, they are a good indicator of the health of these coastal areas.

Scientist in marsh holding live Clapper Rail
Ecologist Scott Rush with clapper rail, Pascagoula River Marshes, Mississippi.
Mark Woodrey, CC BY-ND

Water levels in tidal marshes change daily, and clapper rails have some adaptations that help them thrive there. They often build nests in areas with particularly tall vegetation to hide them from predators. And they can raise the height of the nest bowl to protect it against flooding during extra-high or “king” tides and storms. The embryos inside their eggs can survive even if the eggs are submerged for several hours.

When a tropical storm strikes, many factors – including wind speed, flooding and the storm’s position – influence how severely it will affect marsh birds. Typically birds ride out storms by moving to higher areas of the marsh. However, if a storm generates extensive flooding, birds in affected areas may swim or be blown to other locations. We saw this in early June when Hurricane Cristobal blew hundreds of clapper rails onto beaches in parts of coastal Mississippi.

Clapper rails hiding under a breakwater
Clapper rails on a Mississippi beach after Hurricane Cristobal in June 2020.
Mark Woodrey, CC BY-ND

In coastal areas immediately to the east of the eye of a tropical cyclone we typically see a drop in clapper rail populations in the following spring and summer. This happens because the counterclockwise rotation of the storms results in the highest winds and storm surge to the north and east of the eye of the storm.

But typically there’s a strong bout of breeding and a population rebound within a year or so – evidence that these birds are quick to adapt. After Hurricane Katrina devastated the Mississippi Gulf Coast in 2005, however, depending on the type of marsh, it took several years for rail populations to return to their pre-Katrina levels.

Now we’re radio-tagging clapper rails and collecting data that allow us to determine the birds’ life spans. This information helps us estimate when large numbers of birds have died – information that we can correlate with events like coastal hurricanes.

2020 Atlantic hurricane paths
Summary map of the 2020 Atlantic hurricane season, updated Oct. 27.
Master0Garfield/Wikipedia

Losing parts

Tropical storms have shaped coastal ecosystems since long before recorded history. But over the past 150 years humans have complicated the picture. Coastal development – draining marshes, building roads and reinforcing shorelines – is altering natural places that support marsh birds.

Clapper rails and other species have evolved traits that help them offset population losses due to natural disasters. But they can do so only if the ecosystems where they live keep providing them with food, breeding habitat and protection from predators. Coastal development, in combination with rising sea levels and larger tropical storms, can act like a one-two punch, making it increasingly hard for marshes and the species that live in them to recover.

[Deep knowledge, daily. Sign up for The Conversation’s newsletter.]

Biologist Paul Ehrlich has compared species at risk to rivets on an airplane. You might not need every rivet in place for the airplane to fly, but would you fly it through a cyclone if you knew that 10% of its rivets were missing? What about 20%, or 30%? At some point, Ehrlich asserts, nature could lose so many species that it becomes unable to provide valuable services that humans take for granted.

We see coastal marshes as an airplane that humans are piloting through storms. As species and ecosystem services are pummeled, rivets are failing. No one knows where or how the aircraft will land. But we believe that preserving marshes instead of weakening them can improve the chance of a smooth landing.The Conversation

Scott Rush, Assistant Professor of Wildlife Ecology and Management, Mississippi State University and Mark Woodrey, Assistant Research Professor, Mississippi State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

What ‘The Birdman of Wahroonga’ and other historic birdwatchers can teach us about cherishing wildlife



Shutterstock

Russell McGregor, James Cook University

Under the first coronavirus lockdowns, birdwatching increased tenfold in Australia, with much of it done in and near the watchers’ own backyards. And as Melbourne settles into stage 4 restrictions, we’ll likely see this rise again.

The increase in backyard birding is good news for conservation and can help birds recover from bushfires and other environmental catastrophes. But backyard birding isn’t new, nor is its alliance with conservation.




Read more:
Birdwatching increased tenfold last lockdown. Don’t stop, it’s a huge help for bushfire recovery


Since the turn of the 20th century, when birdwatching as a hobby began in Australia, birders have cherished the birds in their backyards as much as those in outback wilds. Birdwatchers admired wild birds anywhere, for one of their big motivations was — and is — to experience and conserve the wild near home.

Harry Wolstenholme holding a bird in front of him in his garden in Sydney
Pioneering birder Harry Wolstenholme recorded 21 native species nesting in his garden.
Alec Chisholm/National Library of Australia, Author provided

This wasn’t an abstract ambition, but a heartfelt commitment. Birdwatchers have long known that if we are to conserve nature, we need not only the intellectual expertise of science but also an emotional affinity with the living things around us. Birders in Sydney in the 1920s and ‘30s knew this well.

The Birdman of Wahroonga

Harry Wolstenholme, son of the feminist Maybanke Anderson, was an office-bearer in the Royal Australasian Ornithologists’ Union and a keen amateur birdwatcher. In the 1920s, his usual birding site was his own garden in the northern Sydney suburb of Wahroonga.

There, bird life was prolific. Harry recorded 21 native and five introduced species nesting in or near his garden, plus many more avian visitors.

His garden drew a stream of notable birders from the Sydney branch of the ornithologists’ union, such as wildlife photographer Norman Chaffer, naturalist and journalist Alec Chisholm, and businessman Keith Hindwood. (The union members were predominantly male, though with a liberal sprinkling of women, including Perrine Moncrieff who became its first female president in 1932.)

Keith Hindwood in black and white, with a White-eared Honeyeater on his head
Keith Hindwood, with a White-eared Honeyeater on his head, 1929.
Mitchell Library, Author provided

For his closeness to the birds, Harry earned the nickname “The Birdman of Wahroonga”. That suburb still hosts a good range of species, although the bird life is no longer as prolific as in Harry’s day.

Many others birded in city environs and, like Harry, published their suburban ornithological studies in the union journal, The Emu.

In 1932, Alec Chisholm devoted a whole book, Nature Fantasy in Australia, to birding in Sydney and surrounds. Featured on its early pages is a painting by celebrated bird artist Neville Cayley captioned “The Spirit of Sydney: Scarlet Honeyeater at nest in suburban garden”.

Scarlet honeyeater feeding on grevillia nectar
Scarlet honeyeaters can still be spotted in urban parts of Australia.
Shutterstock

The fact this gorgeous little bird was common in Sydney’s gardens exemplifies Chisholm’s theme of urban Australians’ ready access to the wonders of nature. Scarlet Honeyeaters can still be found in Sydney though they are no longer common there.

Mateship with Birds

Like all Chisholm’s nature writings, Nature Fantasy promoted conservation.

Conservation then differed from conservation now, having a stronger aesthetic orientation and less ecological content. Nonetheless, these pioneer conservationists, among whom birdwatchers were prominent, laid the foundations on which environmentalists later built.

Chisholm urged people not merely to observe birds but also, more importantly, to love and cherish them. In his first book in 1922, Mateship with Birds, he urged readers to open their hearts to their avian compatriots and embrace them as friends and fellow Australians.

Jacky winter, a small, pale-coloured bird is perched on a white log.
Early birders believed names of birds like ‘Jacky Winter’ would help us embrace birds as fellow Australians.
Shutterstock

One way of fostering this feeling, Chisholm and his birding contemporaries believed, was to give birds attractive names. For example, “Jacky Winter” struck the right note, and as Chisholm wrote:

it would be a healthy thing if we had more of these familiar names for our birds, bringing as they do, a feeling or sense of intimacy.

While those birders urged people to cultivate an emotional connection with nature, and while most were amateur rather than professional ornithologists, they nonetheless made major contributions to the scientific study of birds.

Science was needed, they realised, but so was feeling. As one reviewer of Nature Fantasy enthused, Chisholm was a naturalist “who in his writings combines with the exact research of a scientist the sensibility of a poet”.




Read more:
Bath bullies, bacteria and battlegrounds: the secret world of bird baths


Birders today

Our city birdscapes have since changed. Some species have dwindled; some have increased. But suburbia still holds a remarkable degree of biodiversity, if only we’re prepared to look.

A woman holds binoculars to her eyes among trees
Lockdown is a great time to try backyard birdwatching.
Shutterstock

The world of the birders of the 1920s and ’30s is gone. Our attitudes toward nature are cluttered with fears unknown in their day, such as climate change. Yet those early birders still have something worthwhile to tell us today: the need to connect emotionally and tangibly with nature.

To hear that message, we need not, and should not, jettison today’s environmental fears. But fear needs complementing with more positive emotions, like love.

Despite — or because of — the prominence of environmental alarms in today’s world, the need to admire and love living things remains as pressing as ever. As birdwatchers have long known, the birds fluttering in our own backyards are adept at fostering those feelings.




Read more:
For whom the bell tolls: cats kill more than a million Australian birds every day


The Conversation


Russell McGregor, Adjunct Professor of History, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.