Using 37 years of data, researchers determined that the jays at Archbold are nesting earlier as a response to warmer temperatures. While early nests typically do better than later nests, there are high rates of nest failures during breeding seasons after warmer-than-normal winters. After warmer winters, even though jays nest earlier, build more nests, and lay more eggs, they have fewer fledglings. 

Why?

The Archbold team suspects that warmer winters mean predators, especially snakes, become active earlier in the following breeding season. Because jays nest only a few meters off the ground, they are particularly vulnerable to these reptilian predators. 

“The Florida Scrub-Jay population might be stable at Archbold now,” explains Archbold’s Director of Avian Ecology, Sahas Barve, PhD. “But even these are not immune to global threats such as climate change. This inspires us at Archbold to work harder to help bring more land under conservation for the jays and effectively manage habitats for the populations we have conserved.”

At Archbold, Florida Scrub-Jay first-nesting dates have advanced by roughly a week over the study period. Even though the number of nests built by each jay pair has increased by 33%, the overall number of successful fledges has declined by 25%. 

Article first appeared in the 2024 Jay Watch season summary.