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The Falco Fingerprint - Working backwards from first summers to move forwards with juveniles

Falco fingerprints are something I have been looking at ever since illustrating and observing raptors and there is a lot that can be said about them.

It all began when looking at recently fledged juvenile Kestrels (falco tinnunculus) and juvenile Kestrels migrating through the Straits of  Messina.
In this post I'm not talking about the wing formula but the patterning on the feather themselves.
I noticed juvenile male kestrels had a unique ventral fingerprint compared to that of juvenile females. I concluded that each primary (digit) had a individuality all of its own and even simple groups of feathers, such as the inner primaries can show a lot about the sex of a juvenile bird when observing raptors against sky.
I intend to post some of my findings in later posts relating to sexing juvenile kestrels but for now I wish to talk about a 1st summer female Red-footed Falcon (falco vespertinus) whose unique fingerprint highlighted quite a nice little migratory path!
For the past 6 month…

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