Thursday, May 19, 2011

Interesting Rose-breasted Grosbeak

This past weekend found us banding at a program in Lakeville Minnesota where we have been banding for several years. The day was fantastic! We had so many birds around and in our nets we had to close the nets after less than an hour and ran out of bird bags. It was the kind of day we will tell stories about for years.

The bird that got us really excited was this Rose-breasted Grosbeak

If you look at the bird you can see lots of indications that this is a second year male. The brown edged feathers, brown primaries, etc. made the age of this bird a bit of a no-brainer but...

This bird was banded! We had banded this bird in 2009 and aged it as a second year bird at that time. If this had been an unbanded bird we wouldn't have thought twice about its age.

So the question I'm throwing out there has two parts. First, has anyone else ever seen a case of a known age RGBR showing characteristics that didn't fit their actual age and second, am I correct to guess that this might be a case of a hormonal condition in this individual?


Anonymous said...

Interesting question. Also makes one wonder if the bird was really a two-year old back in 2009.

Minnesota Birdnerd said...