Mar 19 2009
Question: Why do the female peregrines start laying their eggs at such different times? Is this difference site specific or female specific?
Answer: Egg-laying times are site specific in a macro sense (large-scale geography) and female specific in a micro sense (regional geography). Peregrines who nest in the middle latitudes lay their eggs from mid-March to late-April at a time when arctic peregrines haven’t even left South America for the Arctic yet. Within the same latitude, it’s female specific. The female at Gulf Tower (Tasha) always laid her eggs early, between March 10 and 17. So does her daughter who nests in Cleveland, so I think early egg-laying could be an inherited trait. Other female peregrines at this latitude lay week(s) later than that.
(photo from the National Aviary Gulf Tower webcam)