Saturday, June 24, 2006

How do you tell them apart?

Eldest on the left and Youngest on the right.

How do you tell them apart?

Good question. But today, working on a hunch and using yesterday's photos, I think I've found a way. Be aware though that the cues one uses today, may not hold true in a day or two on these growing birds.

The current easy way when the Divine Fledglings are side by side, is the length of their primary feathers. Eldest's are longer because she is older. But how often do they cooperate by standing side by side, both their backs toward you, so you can see their "wing tips" and compare?

Good luck.

As we do have the view of the primaries we can say as of yesterday which is older and look at the difference in the patterns of their backs to match later which hatched first and fledged first. Currently their backs look quite different. The pattern on Eldest's back makes a pale V with "regular" sections progressing outward from that V. On the other hand, Youngest has a variety of dark more circular "blobs" encircled by pale feathers.

Then there is the question of their sex. Passers-by ask daily whether or not we can tell. The short answer about birds without differentiating plumage is, you wait and see who lays the eggs. But it's interesting to take a look at the Fledglings relative sizes. Being these are both well fed and therefore well grown urban hawks, even with the possible week of difference in age, I've begun to wonder if Eldest isn't a female.

Yes, there are some optical issues to take into account in the photo. And Youngest may be leaning a touch forward. Though not too far as her tail is still touching the molding. Even given that, look at their feet. One can see Youngest's talons but not Eldest's. Eldest is standing deeper but is still taller. She also appears broader, chunkier even though Youngest is showing a more complete view of her back to the camera. Yes there is a slight difference in age. But I'm going to keep an eye on them and see if the little size differences now, which intuit possible "femaleness", come to fruition. Who knows, they may prove to be useful the next time around. If, in the end, Eldest does prove to be a female after all.

So you want to know who's who? Keeping an eye on those primaries and the patterns on their backs will help least for the next span of time. But all the while, do keep a look out for what the next cues to their identity may be. And if you see something, do pass it on and help the other birder have as much fun as you're having telling them apart.

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