29 September 2011 – 2 (and a half) Grasshopper Sparrows

As I rounded the corner to check the south side of the Noble Research Center this morning, I immediately noticed this guy (Grasshopper Sparrow 1 a.k.a. “GS1”) sitting stunned or tired at the base of the building:

Some distance behind him was unfortunate GS2, who must’ve hit a window within the last hour or so:

As I set down my camera and prepared to capture GS1 or flush it away from the building, it was evident that there was still a lot of life left in that little bird.  GS1 flew strongly away from me (west) and started to veer south away from the building.  Just before clearing the corner though, it turned back toward the building and flew up into the external rafters of the south overhang.  These rafters are perches and nest sites for starlings; I had never witnessed a “trapped” bird in them before this morning, but that’s just what happened to GS1.  It fluttered against the windows up to the very top of the rafters and repeatedly flew back and forth the length of the building, apparently unable to figure out how to fly down to find an escape route. GS1 was in the rafters when I left the scene several minutes later.

Hopefully, GS1 will eventually figure it out and fly away none the worse for wear.  That wasn’t the fate of poor GS3.  Apparently, when I arrived there this morning and noticed GS1 and GS2, I did not notice a third Grasshopper Sparrow already up in the rafters and unable to find its way out.  When GS1 flew up to the rafters, GS3 looks to have been spooked and flown into one of the upper windows.  I watched it drop from the rafters and land lifeless on the brick walkway below.

So again, it looks like the unique, angular shape of the Noble Research Center has “trapped” some migrants before collision with the building’s windows led to their death.  Below, GS2 and GS3 await processing on my desk:

Both birds appeared to be adults and in good health (fat scores both = 2).  Today’s survey illustrated some interesting things in addition to the problems birds can have with a building’s architecture.  This is probably the third time I’ve found Grasshopper Sparrows at the south side of the building during fall migration.  What gives?  I think they must have missed a memo.  Also, the tragic scene I came upon illustrates that this species likely travels in small groups.  Actually, for all I know these three could have been part of a larger, loosely organized flock or they could’ve been flying independently but simply ended up in the same place.  Anecdotally, however, it looks like they were flying more or less together.

27 September 2011 – stunned House Wren

I found a somewhat stunned House Wren on the west side of the NRC today.  The little wren seemed to be in pretty good shape except that its right eyelid was closed.  It wasn’t panting or looking otherwise distressed as I walked up and crouched down next to it.  As I tried to catch the bird, it quickly popped up and landed on my right knee.  Then I tried to slowly grab it from behind but it spooked and flew to my left knee.  At this point, the little sprite had fully endeared itself to me.  I tried one more time to grab it and move it someplace more protected, but this time it zipped away from me and flew down one of the west alcoves.  I feared the worst (i.e., that it had flown right into a window), but it must have found a safe spot because it wasn’t waiting for me limp beneath a window.

For now, this House Wren has survived its encounter with the NRC, and I won’t count it as a casualty.  I’ll be a bit extra sad if I happen upon some wren feathers tomorrow morning . . .

13 September 2011 – Ruby-throated Hummingbird

I often leave hummingbirds in place to check scavenging rates, but this one was so fresh I decided to pick it up and really study it.  Of course, hummingbird identification, ageing, and sexing can be pretty tricky, and it’s taken me nearly an hour to figure out this bird with confidence.  I learned a bit along the way, however, so that’s my reward.

OK, it’s a small green hummingbird in the eastern U.S. that is whitish below with some subtle streaking on the throat.  That means it’s most likely a Ruby-throated Hummingbird. On the folded wing, I can see that primaries 1–6 are closer together than primaries 7–10.  That, and some of the other measurements I took, ruled out Black-chinned Hummingbird.

It could be a female (HY or AHY) or an HY male.  A closer look reveals a single gorget feather that has come in red.  Case closed!  It’s a HY male, right?

Well, not quite.  Some AHY females can have a red gorget feather or two, so I had to be more careful in my identification.  I needed to determine the age of this bird, definitively.

Some of the contour feathers on the crown and back were edged in brown.  That should be indicative of an HY bird, but that’s a subjective criterion.  It turns out that the most common technique hummingbird banders use for ageing is to look for “corrugations” on the surface of the bill.  These are faint wrinkles on the bill that fade or smooth out as the bird ages.  Did this bird on my desk have corrugations?

 

OK, kind of, I guess.  But my inexperience with this character still made me suspicious.  I could, however, determine the sex of this bird – definitively – by looking at the shape of the tip of primary #6 (visible in the top photo).  In males, p6 is almost concave and sweeps up to an attenuated point; in females, that shape really isn’t there and the tip of p6 is more truncate or even rounded.

I see the attenuated p6.  Now I’m convinced, it’s a HY male, Ruby-throated hummingbird.

12 September 2011 – Carolina Chickadee

I have recently embarked on my third year of regular window-collision monitoring at the Noble Research Center, and today I was quite surprised by what I found: this HY Carolina Chickadee (fat = 2):

It’s not that chickadees are rare, of course, they are common, year-round residents of every community in the three states in which I have been studying window collisions for the past 15 years or so.  The rare thing is that in all that time, I have never found a dead chickadee at the base of window.  Chickadees are too agile, too familiar with their surroundings, too sedentary, and too slow to end up smacked into a window, or so I thought. Today’s unfortunate little bird is just a reminder that any time a bird finds itself near an expanse of reflective glass, there’s a good chance that the bird will meet its end there.

But it still has me wondering.  Why was this young chickadee in this unlikely location?  Why did it have a good layer of fat laid down?  Chickadees aren’t known to be migratory, but maybe this one was dispersing away from its natal home range.  Maybe the prolonged drought is forcing even our normally sedentary species to wander farther than normal in search of food. Maybe the fact that this bird was on the move was not unusual, but my ability to detect it doing so was. We still have so much to learn even about our most common species.

I took the opportunity with this bird to provide some photos of the process I use in this long-term research.  First, here are some photos of what the bird looked like when I found it.

Here is my processing station on my desk.  I use a wing rule for wing chord and tail length measurements, calipers for bill and tarsus length, and a Pesola spring scale for mass.  My definitive reference for identification, aging, and sexing is Peter Pyle’s Identification Guide to North American Birds, Part 1 (1997).  I write measurements and other details on the back of one of my old business cards.

Finally, I wrap each bird in a tissue and place it in a zip-top bag before it goes to the freezer downstairs. In a week or so, the bird will be prepped as a specimen for the OSU Collection of Vertebrates.