Apr 29 2013
Since the news yesterday that one of the Pitt peregrine chicks died and that the three remaining eggs won’t hatch, many of you have asked questions in email, Facebook and blog comments. Here are some answers, collected in one place.
After consistently raising three to five chicks every season, this year Dorothy has one healthy chick, one handicapped and now dead chick, and three unhatched eggs. It isn’t the cold weather or poor parental care. It’s because Dorothy’s getting old. She’s 14.
Older female peregrines become less fertile. History at other nest sites bears this out. In the last two years of Tasha’s reign at the Gulf Tower she hatched 2 of 4 eggs and 2 of 5 eggs. In 2010, in what was probably her 14th year, Tasha laid two eggs and then was displaced by Dori. At the Terminal Tower in Cleveland, Tasha’s daughter SW is now 14 and has hatched only 2 of 4 eggs. A similar pattern occurred at the Harrisburg site when their female aged a few years ago.
What will happen to Dorothy? Dorothy is my very favorite peregrine in all the world. I don’t like to think of it, but she is mortal just like the rest of us. Frankly, it’s a good thing I can’t predict what will happen. Time itself will tell. Meanwhile I’m pleased as punch that she’s a mother again and has grandchildren, great-grandchildren and — if I only knew where — great-great grandchildren. Go, Dorothy!
Brooding the dead chick: After the handicapped chick died Dorothy drew it back into the nest and is brooding it along with the live chick and her 3 unhatched eggs. I believe she knows the little one is dead but she’s doing what comes naturally — keeping everything warm until she’s absolutely sure. I suspect E2 will remove it at some point when Dorothy is away as he did when one of the five chicks died in 2011.
What will happen to the unhatched eggs? Dorothy will brood them along with Baby until he’s able to thermoregulate and moves off the nest. Brooding lasts 8-12 days but can be shorter in warm weather. When Baby is mobile, the parents will push aside the unhatched eggs where they will either desiccate or rot. Last year’s unhatched egg rotted and smelled awful when it broke on WCO Beth Fife’s shirt during the banding.
Does the empty shell mean another egg has hatched? No, this is an old shell that is swept from here to there by Dorothy’s tail.
Will the only chick do well? If he’s healthy, yes. Baby will get 100% attention from two very experienced parents. Dorothy was an “only child” and is proof that only children can go far.
(photo from the National Aviary falconcam at University of Pittsburgh)