Friday, August 19, 2011

Fall banding 2011 begins

RRBO began the 2011 fall banding season on 12 August. The first week was a "soft" opening, when we put up only a portion of the nets each day, make adjustments, and handle all the young fledglings in the area with some extra TLC. We were also taking some extra time to prepare for a special project, which I'll write about in a future post.

Not too many migrants were present. We caught a Yellow-bellied Flycatcher on 15 August, which was an early date for a fall migrant in Dearborn. A Chestnut-sided Warbler captured on 17 August was the only other passage migrant netted this period. I like the inquisitive look it has.

What we did have was a lot of mosquitoes. This is the worst year for mosquitoes I can remember. In fact, so many come inside with me that they are as bad inside the banding room as many typical years outside.

The coolest bird we caught was not uncommon -- a male Northern Cardinal. But it was a bird we had banded on 19 April 2001 as a second-year bird. Thus, he is now over 11 years old, the oldest cardinal we have recaptured and the second oldest bird we have ever recaptured. While 11 years falls short of the record listed at the Bird Banding Lab web site of over 15 years, it was still good to see him. Over the years he has been recaptured 21 times, but the last time was in 2009.

This is our fifth year of studying the diets of fall migrant birds on campus. We're off to a good start with our sampling of seeds in the poop of various birds. These are all from robins and catbirds.

Just about every species of fruit that is currently ripe has showed up in the samples: grape, pokeweed, glossy buckthorn, dogwood, cherry, and nightshade.

Speaking of robins, three of the six robins we've caught so far have weighed less than 60 grams and have been fairly emaciated. By comparison, only six robins out of over 3500 previously banded here have weighed less than 60 grams, and the average weight for robins is about 78 grams. Generally, I only see birds like this when they are on death's door, and often after they have been exposed to lawn chemicals. I don't have an explanation for the lean condition of these birds, but we'll be monitoring future captures carefully.

Finally, it looks like it may be a very good year, the first in some time, for chickadees. Over the decade between 1992-2002, the resident chickadee population on campus was on the decline. Last fall, there was a large movement of chickadees in eastern North America. It was notable here, and I wrote about it after our last Winter Bird Population Survey season. Clearly, many chickadees chose to stay and nest here, as they were evident on our spring survey as well. We've already banded nine, which is our average over the past nine years. Our high was 52 in 2002. As you might imagine, they are quite the little fussbudgets. I'm happy that their numbers are rebounding, but not so sure I want to band a record number of them.

A Black-capped Chickadee was the first bird banded by RRBO during our inaugural fall season in August 1992. That's right -- this is RRBO's 20th fall banding season. Stay tuned for anniversary-year news.


Michele said...

Have the robins seen after that first week been in better condition?

Julie Craves said...

Well, Michele, yes and no. The young robins we've banded have been in better shape, but we've banded very few of them. I'll be writing about this in my next bi-weekly update in a few days.