Climate Change Could Kill 900 Bird Species by 2100

The resplendent quetzal faces increased competition from other birds and drier habitat due to global warming. Photo courtesy: Matt MacGillivray/CC BY 2.0.

You might think birds, of all animals, could just pick up and move if their environment changes in a way not to their liking, but global warming poses a very real threat to the avian world: Scientists say climate change is likely to drive up to 900 bird species into extinction by the end of the century unless additional conservation measures are taken.

Tropical bird species are particularly vulnerable because they are adapted to living in a stable climate, where temperatures do not vary wildly throughout the year, according to Çağan Şekercioğlu of the University of Utah, the lead author of "The effects of climate change on tropical birds," a scientific review of some 200 separate studies published recently in the journal Biological Conservation.

Surface warming of 3.5 degrees Celsius -- the middle range of the Intergovernmental Panel on Climate Change's latest estimate -- by the year 2100 "may result in 600-900 extinctions of land bird species, 89 percent of which occur in the tropics," Şekercioğlu and his co-authors Richard Primack and Janice Wormworth write. "Depending on the amount of future habitat loss, each degree of surface warming could lead to approximately 100-500 additional bird extinctions."

A red-capped manakin. Some manakin species in Brazil could lose up to 80 percent of their habitat. Photo courtesy: caspar s/CC BY 2.0

The new article, which updates previous research from 2007, looks at different categories of birds (such as "aquatic birds in the tropics," "arid zone species," and "birds in human-dominated landscapes") to assess which will be the most affected by climate change. It also examines how global warming compounds other threats, including habitat loss, hunting, invasive species, pollution, and disease.

"[I]n some cases habitat loss [from agriculture and development] can increase bird extinctions caused by climate change by nearly 50 percent," Şekercioğlu says, calling for further research to be conducted, degraded habitat to be restored, and more land to be protected.

It's not just birds that are at stake. "Farmers, hunter-gatherers, nomadic herders, and others, especially in less developed countries, depend on a healthy environment, and birds are important for ecosystem services like seed dispersal and insect control," The New York Times points out in an article about the study.

And as Şekercioğlu told the paper: "If this is happening to birds, and they can migrate, then for other organisms, it’s going to be worse."

Britain's Birds are Remaining in Countryside This Year

The greenfinch is among common garden birds that have taken their leave of suburbia this winter. Photo courtesy: David Tipling/Alamy

It has been a hard winter for English suburban bird spotters. The nation's house birds have disappeared from towns and cities, leaving gardens devoid of their most familiar feathered visitors.

Their absence has triggered a flurry of letters and emails to the Royal Society for the Protection of Birds from anxious householders disconcerted by the absence of blue tits, greenfinches, chaffinches and house sparrows from suburban Britain.

"We have been inundated with letters over the past few weeks from homeowners who have got used to seeing house birds in their gardens over our recent harsh winters but who are perplexed by their absence this year," said Nik Shelton, an RSPB official.

The reason for the birds' disappearance is straightforward, he added. "House birds like the blue tit or the chaffinch eat seeds or insects, which are easy to find in the countryside when the weather is mild, as it has been for this winter so far. When the conditions get tough, when the ground becomes hard and frosty, it is difficult to get at insects or pick up seeds. Food become scarce, so the birds head into towns and cities in search of sustenance. That is what happened last year and the year before when we had very hard winters. But not this year. Our blue tits and chaffinches are perfectly happy in the countryside at the moment."

The unexpectedly mild conditions have had other disconcerting effects on Britain's birds. For example, woodpeckers can be heard making their distinctive drumming noise in woods, a territorial display that is usually a prelude to nesting and which is not normally heard until later in the year. Jackdaws appear to be equally confused. "The warm weather has convinced them that spring is at hand. It will take a severe cold snap before they can reset their internal clocks and resume normal behaviour for the time of year," added Shelton.

It remains to be seen if that cold snap will occur, however. The Met Office said on Saturday that the weather would remain fairly mild for most of the coming week with temperatures hovering around the average for the time of year. For the longer term forecast, weather patterns are confused, with two very different but equally possible scenarios vying.

"The first scenario consists of changeable weather with rain at times and with temperatures noticeably above average for early February, with only occasional frosts," said a Met Office forecaster. "The alternative scenario is that much colder weather with winds mainly from an easterly or northeasterly quarter, will prevail well into February, bringing widespread frosts and snow to some areas. At present we cannot determine which will happen."

In other words, it is a 50-50 shot if the nation's house birds return to suburbia to avoid the cold of the countryside next month and our woodpeckers stop their drumming.