Great Tits and Climate Change

Great tits have the problem of having synchronise the emergence of their chicks with the availability of moth caterpillars (1000 per day) on which to feed them. A study by the Norwegian University of Science and Technology/ Oxford University has looked at how this species attempts to deal with climate change (https://www.theguardian.com/environment/2021/jan/03/a-wing-and-a-prayer-how-birds-are-coping-with-the-climate-crisis). As the leaves on deciduous trees unfurl earlier as temperatures warm, there is a danger that the moth caterpillars munching on them, may disappear before the chicks have hatched. Great tits consequently attempt to deal with climate change, by laying their eggs earlier. The study demonstrated, however, that there is a 'tipping point'. If Spring comes 24 or more days early, the birds cannot adjust egg laying to compensate for a change of this magnitude. 'Common' garden species may actually disappear.