Many bird species nesting and laying eggs nearly a month early, study says

Species including bluejays, yellow warblers and field sparrows are now laying their first eggs 25 days earlier than they were 100 years ago, the research found. Photograph: Ashwini Bhatia/AP

The arrival of spring has seemingly immutable rituals – lengthening days, blossoming plants and a surge in bees’ activity. But the onset of spring is now being warped by the climate crisis, with new research finding that many species of birds are nesting and laying eggs nearly a month earlier than they did a century ago.

US scientists who analyzed the nesting trends of birds from egg samples collected in the Chicago area found that of the 72 species for which historical and modern data exists, around a third are now nesting much earlier in the year than before.