Blakeman answers a question about the temperature on April 19th

Catherine Labio, Associate Professor of Comparative Literature and French at Yale University, sent in an incisive question for John Blakeman:

In your post of last Friday you raise the following question:

"Since April 19 was an exceptionally hot day here in NYC, is it possible that the mantling behavior observers saw on that day did not signify that a chick had hatched but rather, that it was very hot up there and it was time to cool the eggs off."

I have also been wondering about what effect the heat spike might have had, but what I have been wondering is this:

Could the mantling have indicated that a chick (or more) had hatched, as was initially thought, but that the mantling stopped because the bodies of the chick or chicks were unable to adapt to the sudden spike in temperature and that it/they had died within the first few hours of life? In other words, if the hatching coincided with an abrupt jump to 85 degrees, could that have compromised an eyass's ability to make it through the first day of its life?

I realize that John Blakeman mentioned that "Red-tails are very capable of changing their metabolic rate to maintain constant body temperature." But is that also true of a newly hatched bird?

With warmest regards,

Catherine


John Blakeman sent the following answer:

Eyasses do not have the ability to regulate body temperature. They are effectively "cold-blooded" and must stay tucked up next to the sitting adult to maintain body temperature. But body temperature can vary widely without harm for short periods. The 85-degree weather would certainly have no bad effect on the eyass. In fact, that's about the temperature the little birds would like to have when newly hatched. Red-tails hatched in captive breeding projects have no difficulty with being exposed to 85 degree conditions for moderate periods. The warm weather was a positive, not a negative.