We had an interesting recaptured bird at Carpenter Nature Center last Friday!
We don't have our nets setup right now, it's too cold. Birds tangled in a net can't use their feathers as well to regulate their body temperatures so we don't up them up when it's below freezing. We do set up little cage traps around the feeding areas though. Birds get trapped inside, but they can move around and still use their feathers to stay warm. The above chickadee got into one of the traps and was already banded. These are the birds we really need--recaptures. We can look at the band number, figure out its original capture date, how many times it's been captured, age, sometimes sex, just all sorts of info!
The above black-capped chickadee was banded on July 12, 2002! On its original capture date, the bird was identified as a hatch year bird. So we know based on its plumage that it hatched the summer of 2002. However, we don't know the sex of this particular chickadee. We can only do that in the summer. Females will have brood patches, swollen bare skin for incubating eggs (often called a BP by banders). Males will have a cloacal protuberance for...mating (often called CP by banders).
This six year old chickadee has been retrapped 10 times. Alas, it has always been in the winter. So the first year we banded it, the chickadee was recently hatched and would not have a BP or a CP. And in the winter, males and females are not in the mating mode and they do not have a CP or BP and even though we've had it 10 more times, never at a time when it could sexed.
Still amazing to think that this bird has survived six Minnesota winters. I wonder where it has set up its nesting territory?