Living on the edge - danger for the eyasses

The eyasses are maturing magnificently as their parents provide non-stop food service. However, they are still in danger of falling out of the nest and getting stranded before they are able to fly well enough to return to the nest, as John Blakeman describes below.

Fortunately, the Franklin Institute has the expertise of the Schuylkill Wildlife Rehabilitaion Clinic on standby should anything untoward happen as it did last June when one of the eyasses flew too soon. Check out the June 2009 postings to see how Rick Schubert rescued the eyass and returned her safely to the nest.


From John Blakeman:

"Those of us who watch red-tail eyasses are from time to time alarmed by a most unfortunate, but natural happenstance — something that I sure hope doesn’t happen at the Franklin Institute nest. Still, everyone should understand this phenomenon. It relates to my earlier posting on red-tail slicing, the unique and powerful ejection of fecal matter by both haggards and eyasses.

Even at the earliest age the little eyasses are able to lift their tails high and powerfully eject their slicings out over the edge of the nest. And discerning viewers noted how the little birds, from the earliest days, paid close attention to where they squirted their slicings. Eyasses seem to have a strong and early compulsion to try to make sure they are slicing out toward the edge of the nest, not in to it.

And as they begin to stand and walk around in the bowl of the nest, they make an effort to back up toward the edge before slicing. All of that keeps the slicings out of the nest proper, and helps maintain hygiene. The little birds become naturally potty trained almost from the start.

But, from time to time, a price is paid for these hygienic measures. Sadly, an eyass will get too close to the edge of the nest, and while slicing will simply fall out, tumbling to the ground below. The eyass is almost never injured in its fall, as it’s not very heavy and the short feathers tend to lessen its impact.

The startled bird ends up standing on the ground somewhere beneath nest. Its fate is not assured. Soon, it will start calling for food, and the parents will instantly spot it and will bring food to it. But it’s vulnerable to all sorts of mammalian predators who can find the hapless bird on the ground at night. Unless it can climb into a bush or small tree, the eyass will become prey for another predator.

But usually the bird is able to clamber up into a bush or small tree, often to a good height, away from foxes, dogs, or coyotes. If so, it has a reasonable chance of being fed and eventually learning to fly and hunt.

I just got a call from a hawkwatching couple in California, where one of the two eyasses they were watching was discovered on the ground. I explained all of the above, that this infrequently happens with eyass red-tails, that they do sometimes fall out of the nest when they back up too close to the edge to slice. I advised them to leave the eyass on the ground, or to assist its attempts to climb into a bush or small tree, where the adults could feed it until it got strong enough to fly. These California red-tails are about two weeks older than the Franklin Institute eyasses, so the stranded hawk has a pretty good chance.

If an eyass falls out of the Franklin Institute nest, it would be best for someone to quickly throw a big towel over it on the ground and pick it up and put it in a big cardboard box. Take it inside, in the box, and put the box in a dark room. Then call one of the rehabbers, who will carefully place the eyass back in the nest. It would be a lot of commotion, but no harm will be done.

So, yes, eyasses do sometimes fall out of the nest. When this happens at an earlier age, as at the stage the Franklin eyasses are at right now, most fail to survive in the wild. Predators nail them, or they simply get cold in rains and fail to get enough food from the parents. If there are two remaining eyasses in the nest, parents tend to focus on them, not so much on the stranded bird on the ground.

Actually, there is a much reduced chance that a Franklin eyass will fall over the edge. In fact, there is only one edge of any concern. On one side of the nest, to the right, is a wall. On the back of the nest is the window through which we watch this spectacle. And on the left, out of direct view, is the window ledge upon which the nest sits. So our birds have, perhaps, only a quarter the normal (but low) chance of falling out of the nest."

– John Blakeman