Predicting Bird Patterns

Populations of the most common bird species in Europe and the US are being altered by climate change, according to an international study. 

For the first time researchers showed climate to be having a similar, significant impact on bird populations in large, distant areas of the world. 

Their study used population-predicting models and three decades of field data, gathered by bird-watching volunteers. 

The findings are published in the journal Science.
Led by Durham University scientists, the team developed models that related each species' habitat to long-term climate patterns. 

Using annual climate records - from 1980 to 2010 - these models were able to predict where a species had experienced an improvement or a decline in suitable climate. 

"We then had this amazing data set collected by thousands of volunteers over decades - where people have gone out and counted birds across different countries in Europe and the United States," explained lead researcher Dr Stephen Willis. 

"We can use that to see to what extent our predictions match what people are finding on the ground." 

The outlook is different for each species. Increasing temperatures in the UK, for example, allow some species to expand their range and increase their population, while the same temperature patterns have made the UK a less suitable habitat for others.

But the overall trends, this study shows, are strikingly similar in the US and Europe; populations are increasing in species predicted to benefit from climate change and decreasing in those predicted to be negatively affected. 

"One important thing is that we're looking at the most common birds," said Dr Willis. "These birds are doing a lot of good in the countryside - eating crop pests and helping our ecosystems work. 

"So we need to understand how they'll respond."

The research shows how the climate is gradually remapping the avian habitat across two continents. 

In Europe, for example, birds such as the wren have been increasing in northern areas as winters become milder, but declining in some southern countries. 

The American robin has declined in some southern states, but increased further north.

"This is really the first time anyone's ever looked at changes in climate across two really extensive parts of the world," said Dr Willis.

"So we're getting an idea that [the impacts of] climate change on wildlife are more far-reaching than individual countries."

Birds Determine Local Speed Limits

Recent research suggests that birds can figure out the speed limit on a particular stretch of road.

Biologist Pierre Legagneux of the University of Quebec in Rimouski noticed that common European birds standing on the side of a roadway tended to fly away from an approaching car when the vehicle was at a particular distance from the birds.

The distance varied from one road to another, but not on the actual speed of an approaching car. "They reacted the same way no matter the speed of the car," Legagneux told National Geographic.

Were the birds able to determine the local speed limit (or the average speed of traffic) on certain roads? Daniel Blumstein, a wildlife behavior specialist at UCLA, believes there may be some degree of learning in the birds' response.

A speeding car, for example, could knock a roadside bird off its feet. 

"One or a few trials of getting knocked around may be sufficient for the bird to learn that cars are approaching faster on certain roads than other roads," Blumstein, who was not involved in the research, told NatGeo.

Birds' ability to learn from their environment is a constant source of surprise for researchers. Scientists have discovered, for example, that crows will use stones as tools to raise the water level in a pitcher and snatch a worm floating on the water.

And birds that have a bad experience with humans (such as being trapped and banded for wildlife studies) will remember those particular people's faces — and will teach their friends which humans are the "bad humans," even years after an unpleasant encounter.

Legagneux believes birds that learn to respond to cars based on the speed limits of certain roads have an advantage over those that don't. The birds that don't overreact to approaching cars can spend more time foraging for food (most of the birds studied were sparrows and carrion eaters like crows), while still protecting themselves from any approaching cars.

"This way, they are not spending a lot of time being vigilant by looking at the speed of each car," Legagneux said. The study is published in the latest issue of the journal Biology Letters.

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Original article onLiveScience.