Trump Parc baby development: Q & A with Blakeman

Questions from Mai Stewart, and John Blakeman's answers

I noticed in the photo of Pale Male Jr. + eyasses on today's [6/22] website that the eyasses both have their mouths open, and their tongues also are visible -- I wondered if you have any thoughts as to what's going on -- i.e., are they panting, or eating (?), or maybe chirping, i.e., telling dad they're hungry? There seems to be some prey (?) in the foreground.

Also, do you think that's a feather/s in PMJ's mouth -- or some food for the kids?



Blakeman replies:

Subject:
Re: today's website pix of PMJ w/ eyasses

Mai,

I saw the open mouths, too. The eyasses are being fed, and they will spend a lot of time with their mouths open. The open mouths prompt the parent to pick off some more food and try to drop it into the open mouth.

But all of that will change soon, as the eyasses mature and begin to start grabbing food with both their bills and feet. Soon, they will start tearing apart the food items on their own. Notice that they are starting to stand a bit taller. You can't see it from the camera angle below, but the legs are getting stronger and they will start to sit up on them soon, if not already.

The eyasses are just about to leave the weak, downy stage. Dark flight feathers are beginning to appear at the back edges of the wings, and the body coverts, the smaller feathers covering the body, will soon start to emerge. The birds will grow now at a remarkable rate. They are now able to maintain consistent body temperatures and their digestive systems are running at full throttle.

In the photo, Charlotte indeed has a feather in her bill. It looks to be a pigeon feather, and those things are light and easily stick to flesh being plucked for the eyasses. At the beginning, the parents are diligent in offering only raw flesh tidbits to the little eyasses. But as they mature, as we've seen here, more and more feathers and fur are included. At first, the digestive systems of the little hawks don't handle the fur or feathers well, as they can't easily cough up the ball of fear or feathers from the stomach. Later, as the digestive systems mature, the stomach rolls the feathers into a ball and this is coughed up each day. The expelled pellet or "casting" (the proper term), apparently helps clear mucus or other debris from the stomach and crop.

Falcons in particular require casting material, as falconers have known for centuries. A falcon that is fed only raw meat, with no feathers or fur, will sooner or later become ill or unsettled.

Adult red-tails don't seem to require casting materials for health. But virtually all red-tail foods have them, and the birds expel their castings each morning before going out to hunt. A bit of the loafing the adults do each morning involves the creating and movement of the casting to the mouth. They usually prefer to expel the casting before flying off to seriously hunt.

Biologists love to find fresh hawk or owl castings, as we can pull apart the material and know with absolute certainly what the bird had to eat the previous day. The castings of the Central Park hawks will be mostly pigeon feathers and rat fur, the undigested residue of yesterday's meals.

Of course, the castings of owls also contain the bones of previous meals. Hawks, falcons, and eagles easily digest bones. Seldom is even the smallest fragment of a bone ever found in a hawk casting. But owls have a very different digestive process, and they can only digest muscle. Bones and fur get coughed up, again revealing all that has been eaten.

By the way, as offensive as castings might seem, they are not a health hazard. The powerful digestive enzymes of the stomach destroy virtually all bacteria, certainly any human pathogens. The casting material never even gets into the intestine of the hawk. It stays up in the stomach and crop, so it contains no fecal matter whatsoever. A hawk casting on a Central Park sidewalk presents no health hazard whatsoever (contrasted with the several piles of doggy droppings deposited each day in the Park). A hawk casting is just a rolled-up ball of fur or feathers, nothing more.

Our little eyasses will soon vomit up their first castings, a very significant right of passage that parallels all the other features of growth we getting to watch.

Sincerely,

John A. Blakeman