Daily Archives for January 19, 2017
Australia’s climate in 2016 – a year of two halves as El Niño unwound
Blair Trewin, Australian Bureau of Meteorology
For Australia’s climate, 2016 was a year of two halves. The year started with one of the strongest El Niño events on record in place in the Pacific Ocean, and the opening months of 2016 were generally hot and dry, especially in northern and eastern Australia.
From May onwards there was a dramatic change in the pattern, with heavy rain and flooding a regular feature of the middle months of the year.
Overall temperatures were the fourth warmest on record in 2016, capping off Australia’s hottest decade. We track these events and more in the Bureau of Meteorology’s annual climate summary released today.
Dry to start
At the start of 2016, many parts of Australia were significantly affected by drought. Long-term drought had existed since 2012 through much of inland Queensland and adjacent northern areas of New South Wales, while shorter-term drought affected Tasmania, central and western Victoria, and parts of South Australia.
While some rain fell between January and April in these areas, it was generally not enough to have much impact on the rainfall deficiencies. Tasmania was hit especially hard, with low water storages restricting hydroelectric production, and long-lived and extensive bushfires in central and western parts of the state a feature of the summer period.
January to April, normally the wettest time of the year across Australia’s far north, was also much drier than normal with rainfall well below average in the Kimberley, the Northern Territory Top End, and on Cape York Peninsula.
It was the least active Australian tropical cyclone season since comprehensive satellite records began in 1970, with only three cyclones in the region, none of them severe, and only one of which made landfall.
The rains are here
Widespread heavy rains began in May – something well predicted by seasonal forecast models – as the El Niño ended and conditions in the Indian Ocean became very favourable for Australian rainfall, with unusually warm waters between Western Australia and Indonesia. Each month from May to September was wetter than average across most of the continent, with heavy rains extending into areas such as inland Queensland where the winter is normally the driest time of the year.
The wet conditions culminated in September, when nationally averaged rainfall was nearly three times the average. It was the wettest September on record for New South Wales and the Northern Territory, and in the top four wettest for every state except Western Australia and Tasmania.
May to September was the wettest on record over Australia, with some locations in inland New South Wales breaking previous records for the period by nearly 200 millimetres. Rainfall returned to more normal levels in eastern mainland Australia from October onwards, although Tasmania remained wet, and a tropical low brought widespread heavy rains extending from the Kimberley south through central Australia as far south as South Australia and Victoria in the year’s final days.
Despite flood damage in places and some rain-affected harvests, the wet conditions were generally positive for agriculture. They also led to large increases in water storage levels in many areas, especially in the Murray-Darling Basin and in Tasmania.
Flooding and storms were also a feature of this period. In early June, an East Coast Low affected almost the whole east coast from southern Queensland southwards.
Northern Tasmania saw some of its most severe flooding on record, and the Sydney region suffered significant coastal erosion with some property damage. The heavy September rains led to major flooding on several inland rivers, particularly the Lachlan River in central New South Wales, and went on to produce the highest flood since the early 1990s on the Murray River in South Australia as the waters moved downstream.
An intense low-pressure system in South Australia at the end of September caused major wind and flood damage there. In Tasmania, which had further flooding in November, the seven months from May to November were the wettest on record, after the seven months from October 2015 to April 2016 had been the driest on record.
Over Australia as a whole, it was the 17th wettest year on record with rainfall 17% above the long-term average. Tasmania had its second-wettest year on record, despite the dry start, and South Australia its fourth-wettest. Below-average rainfalls in 2016 were largely confined to parts of the northern tropics, coastal areas of southern Queensland and northern New South Wales, and some parts of coastal Western Australia. Heavy rains in the year’s final week were enough to lift Adelaide to its second-wettest year on record, while Uraidla, in the Adelaide Hills, had the largest annual rainfall total at any South Australian site since 1917.
The heat is on
It was the fourth-warmest year on record for Australia, with temperatures 0.87℃ above average nationally, 0.33℃ short of the record set in 2013.
The year got off to a very warm start; it was the warmest autumn on record for Australia, and the first half of the year was also the warmest on record, although there were no individual heatwaves on the scale of those experienced in 2013 or 2014.
The second half of the year was less warm. During the wet months in mid-year, heavy cloud cover led to cool days but warm nights, then a cool October resulted in spring temperatures almost exactly matching the long-term average. A warm start and cooler finish is typical of a post-El Niño year as rainfall typically changes from below to above average.
It was the warmest year on record in many parts of the northern tropics, along much of the east coast, and in parts of Tasmania. Darwin, Brisbane, Sydney and Hobart all had their warmest year on record. The warmth on land in these coastal areas was matched by warmth in the oceans.
Sea surface temperatures in the Australian region were the warmest on record, with the first half of the year especially warm. The record warm waters contributed to extensive coral bleaching on the Great Barrier Reef, and also affected fisheries in Tasmania.
Temperatures were closer to average in other parts of the country, including inland areas of the eastern states, South Australia and most of Western Australia. In a few parts of southern Western Australia, which had its coldest winter since 1990, temperatures in 2016 were slightly below average (one of only a handful of land areas in the world where this was the case), and there was some frost damage to crops in what was otherwise a very productive year for Australia’s grain-growers.
2016 continues a sequence of years with Australian temperatures well above average. While 2016 did not set a record, the last four years all rank in Australia’s six warmest, and the last ten years have been Australia’s warmest on record. 2016 is also almost certain to be the hottest year on record globally.
Blair Trewin, Climate scientist, Australian Bureau of Meteorology
This article was originally published on The Conversation. Read the original article.
Birdbath, food or water? How to attract your favourite birds to your garden
Grainne Cleary, Deakin University
This summer, when a rainbow lorikeet or kookaburra comes to visit your home, what will you do? Will you offer them a slice of apple, or simply watch until they take flight?
It brings many people joy to provide food and water for birds, to encourage them to stay a while and be given the chance to observe them more closely. But some people are reluctant to interact with birds in this way because they’re worried it might damage the birds’ health.
In contrast with other countries, little research has been done on the effects of feeding birds in Australia. As a result, there are no established guidelines around how to feed and provide water for local birds.
That’s why we ran the Australian Bird Feeding and Watering Study. We asked nearly 3,000 people to monitor the birds that visited their feeding areas and birdbaths. We wanted to know if there was a difference in the species that visited different types of gardens.
We examined the numbers and types of birds visiting:
- birdbaths where no food was provided
- birdbaths where food was provided
- bird-feeders where birdbaths were provided
- places where only food was provided.
The early results from the winter stage of the Australian Bird Feeding and Watering Study suggest that if you provide food and water, you will get more birds in your garden. But the species you attract will depend on what exactly your garden has to offer.
Granivores are seed-eating birds. They include species such as parrots, crested pigeons, sulphur-crested cockatoos, crimson rosellas and galahs.
We noticed a spike in the number of granivores in gardens where both food and birdbaths were provided. But when food was on offer, fewer granivores chose to use the birdbath. We don’t yet know exactly why this is, but it could be because these seed-eaters need less water, or they can get it more easily from other sources than they can food.
Also, most of the bird food sold in shops is seed-based. People who buy these products will naturally attract more seed-eating birds to their garden.
We were, however, surprised to see crested pigeons visiting gardens where food was provided. These birds are only recent urban arrivals, and were previously restricted to semi-arid environments as opposed to the more urban areas where most of our citizen scientists lived. But crested pigeons are very adaptable and now compete fiercely for food and territory with the introduced spotted dove in some Australian gardens.
“Small” nectarivores are nectar-eating birds that weigh less than 20 grams. The main birds in this group are New Holland honeyeaters, eastern spinebills and Lewin’s honeyeaters.
The early results of our study suggest small nectarivores prefer gardens with birdbaths more than their granivore and insectivore friends. In fact, it seems that these small nectarivores like birdbaths so much, they will choose birdbaths over food when both are provided.
“Large” nectarivores are nectar-eating birds that weigh more than 20 grams. These species including noisy miners, rainbow lorikeets and red wattlebirds – seem to prioritise food over birdbaths. This may be because they’re looking for a source of protein that they can’t easily find in their natural environment.
Honeyeaters – such as Lewin’s honeyeaters, blue-faced honeyeaters and noisy miners – will forage on nectar but will eat insects as well. They switch from one to the other, but once they have found their meal they will defend it vigorously from other birds.
Insectivores feed on insects, worms, and other invertebrates. Some insectivore species include superb fairy-wrens, willie wagtails and grey fantails.
Insectivores are most attracted to gardens where both food and water are provided. While superb fairy-wrens were frequently found in gardens where food was provided, willie wagtails and grey fantails preferred to visit gardens where only water is provided.
Many people have told me how confident fairy-wrens and willie wagtails can become around houses and gardens. These tiny birds can be bold and aggressive, and can work together to get what they want. A mum and dad fairy-wrens will conscript their older children into looking after younger ones – and siblings who refuse to help find food and defend territory may even be kicked out of the family. So these tough breeds have a competitive advantage in their new urban environments, and aren’t afraid to mix with or even chase off bigger birds.
You may be wondering exactly what type of seed to put out to attract which granivore, or which meat attracts a carnivore like a Kookaburra. I’m afraid we can’t yet say for sure, as we are yet to analyse the data on this question. Watch this space.
Could birds become reliant on humans for food?
Many people worry that birds will become reliant on humans to provide food for them. But this mightn’t be as big a concern as we once though.
The birds turning up at feeding areas and birdbaths are species that are highly adaptable. Many Australian birds live long lives, and relatively large brains when compared to their European counterparts. Some experts have argued that some Australian birds have evolved a larger brain to cope with feast and famine conditions in the Australian environment.
Many Australian bird species can switch easily between estates and gardens in one area, be semi-nomadic, fully nomadic or seasonally migratory. This ability to adapt and switch between diets makes Australian bird species very resourceful, innovative and adaptable.
Of course, Australia also has birds that have highly specialised diets or habitats, and they’re the ones usually most threatened or limited to one territory – birds like the regent honeyeater or ground parrot. In this study, we’re concentrating on birds that are adapting to urban areas and turning up at birdbaths and feeding areas in gardens.
Building our knowledge of bird feeding behaviour
We plan to develop guidelines around providing food and water for birds in a way that has the highest conservation value for our feathered friends. But before we can do that, we need more data from you.
So please take part in the summer stage of the study and pass the word around to others who may wish to be involved.
The summer survey will run for four weeks, beginning on January 30 2017. Visit feedingbirds.org.auto download the complete report on our early findings or to register to take part in our summer study.
Grainne Cleary, Researcher, School of Life and Environmental Sciences, Deakin University
This article was originally published on The Conversation. Read the original article.