Prothonotary Warbler right - Photo Earl Harrison

Global warming has shifted our seasons. Spring, as defined by the timing of leaf-growing in plants, is coming earlier in eastern North America. And it’s not just a day or two, it’s a week or more for some plants.

Unfortunately, migratory birds don’t time their migration by temperatures or plant growth. How could they? They’re hundreds or thousands of miles away from here when the start heading north. Instead, they rely on day length to tell them when it’s time to move. But if the plants are already past the right point — and the insects that feed on the plants are at the wrong stage — the birds are in trouble when they arrive here. And their chicks are in trouble if the parents can’t feed them the right insects.

You can learn more about this problem in an article on the Audubon Web site.