Why we ‘hate’ certain birds, and why their behaviour might be our fault

Kathryn Teare Ada Lambert, University of New England

We have a complex relationship with wildlife. There are the many species we are encouraged to hate – most typically invasive ones such as cane toads, rabbits and foxes.

There are also some native species, particularly birds, that have a less-than-stellar public reputation too. Often they are the ones that drive out other native species by behaving aggressively and dominating an area almost like a gang, attacking other birds until they get sick of it and move away.

If any other species enters their habitat and they see it as a threat, these birds defend their territory by chasing, pecking, swooping and annoying the individual until they give up the fight and flee. Some large species also steal our food and damage livelihoods, are aggressive towards people who pass through their territory, or just annoy us by making huge amounts of noise.

Naughty and nice

Prevailing views of which bird species are “nice” or “nasty” can actually influence landscapes, because residents with gardens can basically be thought of as being like very small-scale wildlife managers. In the United States, a recent study of more than 900 Chicago residents found that backyards were more likely to contain bird-attracting factors such as fruit trees or complex vegetation, compared with front yards that were more typically influenced by the need to impress the neighbours.

But if people evidently enjoy having birds in their backyards, it seems they are happier with some species than others. A UK study that documented the “likeability” of various bird species found that songbirds were preferred over non-singing ones, and that people tended to enjoy seeing a variety of species in their gardens, rather than one dominant one.

A miner problem

Let’s look at two prime examples native to Australia: the Noisy Miner and the Bell Miner. Both of these birds are particularly pugnacious honeyeaters that noisily defend their “patch” of trees and chase away other birds.

Because of their respective vegetation preferences, the Noisy Miner has increased in number in urban areas such as parks, golf courses and backyards, whereas the Bell Miner has flourished in disturbed forest areas where the understorey is thick and lush.

Bell Miners hardly get ringing endorsements from gardeners.
John Manger/CSIRO/Wikimedia Commons, CC BY

Both species aggressively defend their territories from smaller insectivorous birds, which reduces species diversity. And both are associated with the plant sickness known as dieback (particularly Bell Miners, which have their own version named after them, called Bell Miner Associated Dieback).

You might think it’s little wonder that these birds are hated by many members of the general public, who would rather have them removed than living in their backyards and nearby national parks.

But is it really the birds’ fault or are we causing all the problems?

The short answer to the first question is no. Both species are Australian natives that live naturally in forested ecosystems, where they do not “take over” habitats. In undisturbed wild areas they exist in balance with vegetation and other bird species.

But the human disturbance of forests through urbanisation, fragmentation, vegetation degradation and the spread of weeds has allowed both species to increase significantly in number, helping to “tip the scales” in their favour.

The Bell Miner and the Noisy Miner are becoming “winners” in this case, while specialist species like the Regent Honeyeater, which relies on nectar-producing eucalypts, are becoming “losers”.

Within the fragmented habitats, trees have also become stressed, which reduces flowering of eucalypts. In the case of the Noisy Miner, its diet typically comprises 25% nectar and 75% insects, so the loss of nectar can be compensated by other food resources. It is also thrives in areas of open understorey, where it can easily dominate over other avian species.

Smaller birds in these areas may be more open to predation or weather and therefore flee the area. What’s more, Noisy Miners also benefit from smaller remnants and a reduction in canopy tree density, which creates an open habitat that is perfect for mobbing other birds.

Although less research has been conducted on the habitat preferences of the Bell Miner, our study suggests that they could prefer areas with a thick understorey, canopy trees and no midstorey, regardless of which plant species are present. They also seem to have a generalist diet similar to the Noisy Miner, featuring a variety of insects including caterpillars. The combination of this feeding behaviour and habitat preference may have allowed the Bell Miner to flourish in areas invaded by weeds such as Lantana.

All of these changes have actually been caused by people. We have removed and changed the habitat to a huge extent, and some bird species have benefited greatly while others have suffered.

Sowing the seeds of recovery

So, if we are the culprits, what can we do? By planting more native plants in our gardens, we can encourage other bird species and make it less likely they will be chased away by dominating species. If everyone did it, this would create entire landscapes where bird communities are much more healthy and diverse.

You can also get involved in bird monitoring. BirdLife Australia runs citizen science projects to which you can contribute and which will also show you how healthy your backyard is for birds.

BirdLife Australia’s Birds in Backyards project

Birds in Backyards is a research, education and conservation program that was created in response to the loss of small native birds from our parks and gardens, and to the loss of native bird habitat due to the rapid expansion of the urban landscape.

If you’re in Sydney, you can get involved with the Noisy Miner survey, which aims to determine where these birds are living. Who knows, you might even grow to like them.

Kathryn Teare Ada Lambert, Research Associate, University of New England

This article was originally published on The Conversation. Read the original article.

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Six burning questions for climate science to answer post-Paris

John Church, CSIRO; Alistair Hobday, CSIRO; Andrew Lenton, CSIRO, and Steve Rintoul, CSIRO

Much has been written about the challenge of achieving the targets set out in the Paris climate agreement, which calls for global warming to be held well below 2℃ and ideally within 1.5℃ of pre-industrial temperatures.

That’s the headline goal, but the Paris agreement also calls for a strong focus on climate science as well as on curbing greenhouse emissions. Article 7.7c of the agreement specifically calls for:

Strengthening scientific knowledge on climate, including research, systematic observation of the climate system and early warning systems, in a manner that informs climate services and supports decision-making.

The next paragraph also calls on countries to help poorer nations, which have less scientific capability, to do the same.

But what are the many elements of climate science that need strengthening to achieve the aims of the Paris agreement? Here are six questions that need answers.

What do the targets mean?

What do the 2℃ and 1.5℃ targets imply for our climate and adaptation responses? Even warming of 2℃ will have significant impacts for humans and natural systems, albeit much less than would occur if we allowed warming to continue unchecked. Still, climate science needs to clarify what is gained by meeting the 1.5℃ and 2℃ targets, and the consequences of missing them.

Are we on track?

It will be essential to monitor the climate system over the coming years and decades to see whether our efforts at curbing warming are delivering the expected benefits, or if more measures are needed.

The path to these ambitious temperature targets will not be smooth – there will be periods of rapid warming interspersed with periods of slower warming. We will not meet the targets if the world relaxes on mitigation efforts because of a short-term slowing in the rate of warming as a result of natural variability, such as we saw between 1998 and 2013.

Greenhouse gas concentrations, global temperatures, rainfall and water balance changes, extreme weather events, ocean heat content, sea level and terrestrial and marine carbon sinks are all vitally important elements to track. A focus on surface temperature alone is not sufficient.

What are the tipping points in the climate system?

Tipping points are thresholds beyond which there will be large, rapid and possibly irreversible changes in the climate system. The Greenland and Antarctic ice sheets are one example – beyond a certain level, warming will cause large and irreversible loss of ice, and sea level rise of many metres over the ensuing centuries. Thresholds also exist for ecosystems, such as the Great Barrier Reef, and the services they provide, including food production and water supply.

We need to know what these thresholds are, the consequences of crossing them, and how much and how fast we will have to reduce emissions in order to avoid this.

How will climate and extreme events change?

Many places already experience weather extremes such as heatwaves, droughts, fire, floods, storm surges and cyclones, all with damaging consequences. Many of the negative impacts of climate change will occur through changes in the magnitude, duration and frequency of these extreme events.

To adapt to these changes and manage the risks, more detailed information is needed on local and regional scales. It is important to recognise that 2℃ of globally averaged warming does not imply 2℃ everywhere (many regions, particularly on land, will have larger temperature rises). Extremes may increase faster than averages.

We also need to understand the short-term (decades) and long-term (centuries) implications of choices made today.

What are the appropriate adaptation pathways?

Even if the Paris targets are achieved, some adaptation will be essential. So how do we reduce vulnerability, minimise costs and maximise opportunities? Given the changes already observed with the roughly 1℃ of global warming so far, it’s fair to say that more severe impacts will occur during this century.

Keeping warming within 2℃ and moving to a lower-carbon world presents many challenges. Considerable work will be needed to help identify climate-resilient pathways and allow humans to adapt to the changes.

Successful adaptation will require an ability to foresee and prepare for inevitable changes in the likelihoods of extreme climate events from year to year. Development of climate forecasts on timescales of a year to decades may provide opportunities to reduce losses in critical sectors such as water, agriculture, infrastructure, tourism, fisheries, energy and natural resources.

Can we take greenhouse gases back out of the atmosphere?

Most scenarios for future emissions that keep warming below the agreed Paris target require not just a reduction in emissions, but also the ability to reduce greenhouse gas concentrations in the atmosphere – so-called “negative emissions”.

One proposed method of partially meeting our energy needs and reducing CO₂ concentrations is called BioEnergy Carbon Capture and Storage. It would involve growing biofuels for energy, then capturing and burying the carbon dioxide released by these fuels. While potentially important, its large-scale deployment poses important questions regarding its costs and benefits and how the large amount of agricultural land required would compete with food production to feed the world’s growing population.

To keep climate change below 2℃, some have proposed a need for more radical geoengineering options if emissions are not phased out quickly enough. These include schemes to cool the Earth by reducing solar radiation. But these proposals fail to address other knock-on issues of carbon dioxide emissions, such as ocean acidification. They also pose large risks, are beset with ethical issues and beg the question of who is going to take responsibility for such schemes.

The Paris agreement proves that the world’s nations know we need strong climate action. But society faces tough choices as we seek to find economically, socially and environmentally feasible ways to meet the targets. Informed decisions will depend on robust science at both local and global scales, which means that far from being done, climate science is now more important than ever.

John Church, CSIRO Fellow, CSIRO; Alistair Hobday, Senior Principal Research Scientist – Oceans and Atmosphere, CSIRO; Andrew Lenton, Senior Research Scientist, Oceans and Atmosphere, CSIRO, and Steve Rintoul, Research Team Leader, Marine & Atmospheric Research, CSIRO

This article was originally published on The Conversation. Read the original article.