As regular CFZ-watchers will know, for some time Corinna has been doing a column for Animals & Men and a regular segment on On The Track... particularly about out-of-place birds and rare vagrants. There seem to be more and more bird stories from all over the world hitting the news these days so, to make room for them all - and to give them all equal and worthy coverage - she has set up this new blog to cover all things feathery and Fortean.

Monday, 13 May 2013

Climate change not effecting Great tit populations - More hatchlings die - More juveniles survive

Wild populations of great tits and earlier springs - Courtesy of The Norwegian University of Science and Technology (NTNU) 

May 2013. What happens when climate change makes for a food timing problem for great tit populations? Norwegian, French, American and Dutch researchers have explained (In Science magazine) that while more hatchlings may die, greater juvenile survival and immigration have surprisingly kept populations stable. 

Earlier springs
One of the many changes that results from global warming is a shift to earlier springs - something that has led many biologists to worry what will happen to populations that have adapted to specific events with precise timing when that timing shifts. 

Caterpillars hatching earlier
Earlier springs have caused caterpillars to hatch and grow earlier than they used to. But great tits, which catch caterpillars to feed their young, have not been able to advance their timing of egg-laying to keep pace with the caterpillars. This has caused an increasing mismatch between the peak availability of caterpillars and the hatching of baby great tits, which has caused early offspring survival in great tits to decline. 




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