Monday, May 19, 2008

What about that littlest falcon chick?

Many have noted one of the chicks is smaller than the others and sometimes is not being fed. It is normal for there to be varying sizes between the chicks. Some possible reasons:
Male vs. female: female peregrines are larger than males and this size difference is even apparent at banding time. The difference in size is so dramatic that the males are fitted with a smaller size leg band!

Age: the last to hatch is simply the youngest. Let me clarify which egg was the last to hatch. I reread my update from when the 4th egg hatched and realized that I implied in the update that it was the first egg that was laid that hatched last. Even though that was the natural school of thought with everything playing out like it did, it is likely not the case. In retrospect, the first egg to hatch could have been the first egg that was laid.

How it works: the embryo only begins to develop when incubation begins full time. An unincubated egg is basically in "limbo" until consistent warmth from the incubating adult allows it to begin to develop. Usually, when peregrine eggs are laid in a normal time frame of 1 egg every 2-3 days with incubation beginning after the last (or next to last) egg is laid the period of limbo for the first egg might be 6-9 days for a clutch of 4. It was unusual this year that 8 days passed between the first egg and the 2nd which stretched the "limbo" period out even longer for that first egg. But, when you consider the nesting habits of a mallard duck, the period of laying can stretch out for quite some time: one egg every day or so times as many as 15 eggs in a clutch before incubation begins = a long time! So, looking back, it maybe isn't as much of a surprise that all 4 eggs hatched after all. As long as it doesn't cook or freeze, an egg can remain viable for a long period. (This was a lot of explanation to make the point that the first egg laid several days prior to the rest of the cluth did not necessarily result in the "runt of the litter!")

So, if there is a smallest chick, which egg did it come out of then? Hard to say for sure and it really doesn't matter as we now look at whether or not the little one is getting fed enough:
It is normal for there to be chicks more aggressive than others. At feeding time it happens that usually the bigger, more aggressive nestlings get fed first and the smaller one(s) might not get fed or fed as much. But, once the aggressive one(s) are full then they aren’t as pushy and the smaller one(s) get fed first the next feeding. Then, the next time after that the aggressive one(s) are hungry again and they get fed first again. In the big picture it usually ends up working out pretty even.

But, sometimes there can and will be problems. That’s one disadvantage of having the cams is that we see a LOT more of what normally goes on. Having a front row seat to mother nature can be exciting, educational and sometimes upsetting all at the same time. Luckily, things seem to be going very well with the Columbus nest and all four chicks look good!

P.S. We've gotten a lot of positive response from my post last week reminding folks that the Ohio Division of Wildlife's peregrine falcon management is funded by donations. Thanks to everyone for your support!!!