Long-Tailed Tit May Benefit from Climate Change

The long-tailed tit - a tiny bird native to Europe and Asia - may be on the winning side of climate change, according to researchers. As the weather gets warmer, the bird, which typically dies in large numbers during cold winters, is expected to thrive.

Writing in the journal Oikos, the researchers from University of Sheffield and the British Trust for Ornithology report their 20-year study of the long-tailed tit, noting that warmer spring months may be the bird's salvation.

"During spring, birds must work their socks off to raise their chicks," said study leader Philippa Gullett, a PhD student at University of Sheffield. "For most small birds that live for only two or three years, not raising any chicks one year is a disaster. They might only get one more chance, so they can't afford to fail."

The researchers found that long-tailed tits that breed during warm and dry spring months have better odds of surviving the following year.

"If it's cold and wet in spring, that makes their job much tougher," Gullett said. "Food is harder to find; eggs and chicks are at risk of getting cold. The result is that by the end of the breeding season, the adult birds are exhausted."

Long-tailed tits go to great lengths to raise their young, and the energy they expend trying to care for a nest full of chicks during cold weather can often be the catalyst for the bird's death. The predictably cold winter months, however do not seem to play a role in the bird's death rate. It's the weather of the seasons on either side of winter that seem to have the biggest impact on long-tailed tit survival.

"We're not saying that birds never die in winter - in harsh years there are bound to be some fatalities," said University of Sheffield's Karl Evans. "However, it seems that in most years autumn weather plays a bigger role, perhaps acting as a filter that weeds out weaker birds before the real winter hits."

The researchers said that autumns may get wetter over the years to come, but warmer spring and summer months will offset any overall increase in mortality due to colder autumns.

"Looking ahead to the future, our data suggests that every single plausible climate change scenario will lead to a further increase in long-tailed survival rates," Evans said. "While many species struggle to adjust to climate change, these delightful birds seem likely to be winners."