Wednesday, September 5, 2007

That Bonk on the Window

Wednesday, September 5, 2007
While sitting in the photo blind, the weekend before last, I watched a red-eyed vireo chase a smaller, frightened bird across the yard that runs along the north side of the house. Red-eyed vireos in autumn seem to get a surge of hormones or adrenaline that makes them spend absurd amounts of time and energy chasing other birds.

Why do they do this? I assume it's the hormonal effects of the seasons changing. Why do the chased birds flee? If you had an olive-green hornet of a bird with a dark crown, white eyelines, a stout bill, and red eyes flying directly toward you, would you sit there on your comfy perch yawning? Or would you head for deep cover?

The next sound I heard, after a "stop-chasing-me!" squeal was a sickening thunk. And a bird fluttering to the ground beneath the large glass windows of the studio.

I summoned Julie and she, after searching the ground in the flower bed, found a male yellow-throated warbler, slightly stunned by its glancing encounter with the window.

Each fall we get a number of yellow-throated warblers on our ridge-top farm. They seem to want to see what the view is like from the top of the ridge. This vantage point certainly offers more of a view of the landscape than their sycamore-tree habitat along river bottoms and creek beds. As a young birder in the early 70s, I knew this species as the sycamore warbler.

Our bird-strike-susceptible windows have FeatherGuards on them which help to reduce the number of window strikes by a large percentage. Still there is no stopping a panicked warbler with a heat-seeking vireo on its tail. Fortunately the strike was at a severe angle, so the impact was not forceful, and the warbler was already recovering when Julie picked it up. She held it for a few minutes to make sure it was on the mend (Julie is a licensed bird rehabilitator), then placed it in our birch tree.

Birds that have hit a window always appear dazed. They gape (bill open) and blink slowly. This male yellow-throated gathered his wits slowly but methodically, so we knew he'd survive the impact. (Many birds suffer a head trauma sufficient to kill them long after the impact).

Soon our bird was perching on his own, though not yet ready to take wing. We watched him from a respectful distance, snapping a few pictures with our telephoto lenses.

Recovering birds often gape while gathering their wits.

Bill closed, a good sign.

The first movement along a branch, the normal foraging maneuver of this species.

The following day, a male yellow-throated warbler stopped by our birch tree and spent about 20 minutes preening and chipping in the open. We thought it might be our same bird, come back to visit the scene of the accident.

He was in fine form, preening and foraging along the branches like any healthy member of his species would do. He LOOKS like the same bird, but of course, we can't be sure.

Looking fully recovered (if this is the same bird).

Preening like a wild man.

Ready for his close-up.


On September 6, 2007 at 10:28 AM Anonymous said...

Why DO the bird seem in such discord this time of year? The goldfinches, chickadees, nuthatches, and most other birds are chasing each other constantly. The hummingbirds seem especially agressive and twice this week, I've retrieved hummers who hit the house. Fortunately both survived and I had the great opportunity of holding them until they recovered and flew away.

Is there a rhyme or reason? Many of these birds will not migrate so it can't be simply a food fight. And they are obviously not nesting now. I just don't get it.

On September 6, 2007 at 2:17 PM Mary said...

There's nothing worse than hearing that "bonk". I always jump and search outdoors, taking care to keep the dogs inside, hoping for the best. Unfortunately, it's not always good.

I have noticed the birds being antsy lately - especially the hummingbirds.

Beautiful photos of a fortunate little bird!

On September 6, 2007 at 2:40 PM Janeyms said...

I hate those bonks, here we have huge plate glass windows looking out over the fields and I really enjoy sitting in my great room watching the birds at my feeders. This year we had a kamikazi hummingbird who was determined to get in the house to feed off my flowering hanging baskets. I finally had to remove them from the window because this youngster would not give up and I was so worried about that dreaded bonk. He was just too pretty to chance it. Unlike Julie I have no idea how to resuscitate a hummingbird.

On September 6, 2007 at 3:55 PM Jayne said...

I never heard the "bonk" when a baby Downy hit my house. :c( So glad this little one was OK and only dazed. Magnificent photos of a not too common visitor! Thanks for the link on the Feather Guards... may have to get some!

On September 6, 2007 at 5:56 PM KGMom said...

Ok--since I don't know birds, why would a red eyed vireo CHASE the warbler? Territory? Food? Just plain pissed?
Glad you two were there to set the warbler back on his feet.

On September 6, 2007 at 7:40 PM KatDoc said...

Awesome photos of a fabulous (and lucky!) bird, Bill! Certainly not a "confusing fall warbler," that's for sure. Can you put it in your pocket and bring it along to Lakeside this weekend?

I was noticing the bird's bill in one photo (the one right after the panting shot, where it was closed) and thought how big and heavy it looked, not what I think of as a tiny, pointy warbler bill. Then, I remember a BWD article on warbler bill types ("pliers vs tweezers" was the analogy, I think) but I can't find it.

I get my fair share of "bonks" on my enclosed back porch (glass on 3 sides) but so far, they have all been DOA. I have some falcon silhouettes up, but that doesn't help much. I moved a bird feeder, which was in a bad location. That did help some, but I may have to invest in Feather Guards if I see problems this fall and winter.

Keep up the pretty pictures - no "gutpiles," please.


On September 6, 2007 at 7:45 PM KatDoc said...

PS: I forgot to ask. Why, oh why did they ever change the name of this bird? "Sycamore warbler" was so right, and certainly made it easier to remember the name - "What is that warbler in the sycamore tree? Oh, yeah - Sycamore Warbler." Now, you have to be so careful to pronouce, "That's a Yellow-throatED Warbler over there." Obviously loking at a Common Yellowthroat there is no way to mistake it for a Yellow-throatED, but saying it quickly to someone in the field gets tricky.

My second-least favorite name change. (Number one is the change from Rufous-sided to Eastern Towhee.)


On September 6, 2007 at 8:59 PM Bill of the Birds said...

I think the REVs chase birds in the fall because they (the vireos) are full of raging hormones--sort of a late-season mini-breeding season rush. And it makes them krazy. So they chase after any other bird.

It also could be that it's just a lot of fun.

On September 7, 2007 at 10:09 AM dguzman said...

Beautiful! I wish I had more migrants in my yard; I think it's too open (being surrounded on all sides by a marsh and the road). Trees, but not enough trees.

I have those window decals of large leaves that seem to do the trick of keeping the BONKs to a minumum.

And nice badonkadonk shot! Love your pop culture sensabilities!

On September 10, 2007 at 9:45 AM Science Chimp said...

The ornithologists call it gonadal recrudescence. The gonads swell and start putting out testosterone to give the birds that "extra little push over the cliff"--to take them up to eleven, so they can migrate. But, like gin, it makes them mean.