Questions of age have come to my attention from a few readers about the south side female. Yes, she is getting “a little long in the tooth” and according to “Birds of North America,” the peregrine falcon article, female age has a significant effect on all measures of reproductive success: clutch size, fertility, hatchability, brood size, nestling survivability.” What they are saying is that a fourteen year old female will not lay as many eggs as she did in her younger years. Some of her eggs won’t be fertile, some of the fertile eggs won’t hatch.
I have watched the same female since she arrived at Morro Rock in the summer of 2001 as a subadult. She still carried vertical barring of a juvenile on her chest. I believe her to be 13 to 14 years of age. The article states further that the older they get , there will be fewer eggs produced. This female had her largest clutch last year, four in number. In the wild most peregrine observers believe the average lifespan to be 16 to 20 years. In captivity, 25 or more years. Weakness in an aging peregrine will become evident to other peregrines and a younger one will eventually replace her. We haven’t seen any of these distinct signs. If this season is a failure, it’s not because she didn’t try… twice! I hope we’ll both be here next spring.
Happy trails, Bob
First: Although we are both in our “golden years,” she hasn’t changed a bit where as I … What happened?
Second: After observing from 4 to 6 hours daily, we haven’t seen any activity around the second nest site since July 2nd. We did see both tiercel and falcon go into the “diving board” nest site, the previous nest site. Now what? It is getting late in the season….