Saturday, August 28, 2010

Fall banding 2010: Week #2 in review

Warblers welcome!

Week #2 was abbreviated due to my participation on a state advisory panel. The modest totals for the week were 59 birds of 21 species, plus recaps and another batch of hummingbirds released unbanded. Returns of birds banded in previous years included a female American Robin from 2007, and a Gray Catbird from last fall.

The best part of early fall is the nice variety of warblers that start to come through. Later, we'll have higher numbers of some species, or more diversity of birds overall. But this early in the season there is a nice parade of often-subtle, but always pretty, warblers. Here are a few from this week:

Blackburnian Warbler.

Chestnut-sided Warbler. Am I the only person who thinks the green looks like the color you get when you use a yellow highlighter on newsprint?

Black-and-white Warbler.

Wilson's Warbler. Audubon called this species "Wilson's Flycatching Warbler" and you can tell they do some aerial flycatching by the "whiskers" around the bill, known as rictal bristles. They help trap small flying insects.

Tennessee Warbler. More of a gleaner, it lacks the long rictal bristles of the Wilson's Warbler and uses its sharp bill to probe leaves for insects.

One thing we note when we band Tennessee Warblers is the presence (and size) of a white spot on the outer tail feather. About 30% of adult and 20% of hatching-year birds have this spot at our site, and usually if it is present in hatching-year birds it is smaller than this.

Other highlights this week included our first Swainson's Thrush, one of my focal species in my study of use of resources during migratory stopover.

The biggest thing I got in the nets was a female Cooper's Hawk. This is only the third Coop we've caught at RRBO, since they are generally too large and heavy to stay in the nets; and the first female, which are larger than males.

I've been grabbed by little male Sharp-shinned Hawks, which are only about the size of a flicker, and they have needle-sharp talons than can hardly be felt going in...but can be a real problem when the bird starts tugging to get them out! This big female Coop had talons to be respected and very long legs. It's times like these I'm glad I always carry too many bird bags. I handed her a wad to grab onto until I could secure her legs. Really, you can never let go of the legs when handling a hawk, so banding one is much easier as a two-person job. As luck would have it I was working alone and nobody was even in the building to snap some photos. Everything went without mishap as she was quite calm and cooperative, but I wished I could have photographed her eyes -- she had the very green-gray eyes of a young bird (soon to turn yellow and eventually red). That and the fact that her back feathers had extensive rufous tips may indicate she was hatched locally and not a migrant from farther away.

With hawks you worry about the feet, with Rose-breasted Grosbeaks you worry about getting bitten. That bill is very strong and while I've never had one draw blood, they pinch so hard you get left with a divot on your finger that lasts for hours. Plus, they just have nasty dispositions. This adult female didn't nip me, since I've handled enough of them to know not to be careless and always put them in a distinctive colorful bird bag so I don't get surprised when I reach in.

The weather forecast for at least the beginning of next week sounds like a return to summer; not very conducive to migratory movement. We'll see what ends up in the nets.

A reminder that we are moving the RRBO web site in the next few days. Please use this URL to access the current/soon-to-be-replaced site, it will continue working: and use my long University address (jcraves AT umd DOT umich DOT edu) or gmail address (jac DOT rrbo AT gmail DOT com) to contact me. Don't use the jac AT rrbo DOT org until further notice.

I'll be posting frequent updates here -- I'm very excited about the new site and can't wait to hear what you think!


Jerry Jourdan said...

Wonderful pics, Julie!

The Zen Birdfeeder said...

Great post, great pix, would've loved to see that Coopers.

Greg Norwood said...

I'm glad you mentioned the wonderful pace and variety of the fall passerine migration at RRBO. I think it is the best season for birding there because of the relative consistency of the daily arrivals. On Saturday, I had three magnolia warblers in the single hawthorne at the south end of the lake and watched them glean invertebrates after first noticing them by the snapping of their bills!