BirdFeedingMismatch_1024w_DE.jpg
This illustration is based on the long-term study in the Hoge-Veluwe National park conducted by Marcel Visser and Phillip Gienapp:
The left panel shows the situation in 1980 when the food-need and -supply were still in-sync. The right panel shows the situation today: during almost 25 years the great tits in this region have moved their egg-laying only about one week forward but the caterpillars were able to shift by two to three weeks. As a result of this, the peak availability of caterpillars is already over by the time the chicks hatch and the adults no longer find enough food to feed their young in the especially critical time 8 to 10 days after hatching. This can lead to loss of chicks in any given year and is therefore a big problem for the long-term outlook for this bird in this region (great tits in other countries seem to be more adaptable and therefore don’t necessarily have this problem).
BirdFeedingMismatch_1024w_DE.jpg
BirdFeedingMismatch_1024w_NL.jpg
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