Late birds are missing the worm
When songbirds return from their southern wintering grounds to North America, they're aiming for the "green-up," when flowers and leaves are blooming, and their insect food is at its most plentiful. Climate change, however, has been shifting the timing of spring green-up.
In a study of 48 species of North American songbirds, Canadian biologist Stephen Mayor from the University of Florida combed through data gathered by ornithologist "citizen scientists" on when birds have been returning. What he found was that while some species are pretty good at moving their migration times to track the changing time of spring, nine of the species he studied were having a lot of trouble – missing it by nearly two weeks.
This could have important impacts on their nesting and reproductive success, and also the services they provide for humans, like spring insect control.
Paper in Nature Scientific Reports: Increasing phenological asynchrony between spring green-up and arrival of migratory birds