We have a bird video from reader Art in Ohio:
We have been following the development of three noisy but adorable wood thrush chicks (Hylocichla mustelina) and their industrious parents. Here is a short video of them feeding.
And reader Will from Morris, Illinois sends a strange example of animal behavior.
Today, I observed and photographed (attached) odd behaviors in Cooper’s Hawks (Accipiter cooperii) in my backyard in Grundy County Illinois. Three juvenile (?) birds landed and two of them “bowed down” to the third bird. This lasted about two minutes before they were startled by something and flew off. I’d guess this was a mating display but they seem to be juveniles. Strange.
Will updated me this morning; the behavior is well known:
Dr. Robert N. Rosenfield promptly answered my query about this behavior in Cooper’s Hawks. He directed me to his paper in the Journal of Raptor Research, “Proning Behavior in Cooper’s Hawks (Accipiter cooperii)“.
The behavior, which Rosenfield and coauthor Larry Sobolik call “proning” (good word!), may be a way to avoid detection by predators, or it may simply be a “byproduct” expression on the ground of a behavior that these birds normally show in the nest. A quote from his short paper:
. . . It is routine for older nestling and fledgling Cooper’s Hawks and other young raptors to lie down on the nest to rest and/or sleep.
. . . Reynolds and Wight (1978) indicated that researchers may overlook fledged accipiter young, and hence underestimate reproductive output, in part because young occur farther away from the nest as they develop flying skills. These liabilities may be aggravated by reduced detection probability associated with proning because a proning bird away from the nest likely ‘‘blends’’ in with the branch on which it is lying (Fig. 1), or it may be overlooked when on the ground (or on a house structure
Here’s figure 1 from Rosenfield and Sobolik’s 2004 paper along with its caption:
And Stephen Barnard has contributed a photo of a Cedar Waxwing (Bombycilla cedrorum) I’ve always said that if a running shoe could fly, it would look like this bird:
To me this hawk behavior is just an example of a common bird behavior, sunning to clean parasites.
Art, Wood thrushes are plain browm above. The birds in the video can’t be wood thrushes.
“browm” >> brown
Nice video by the way.
The streaky head makes me think it’s a song sparrow.
I was thinking at first that the lying down behavior was to practice ‘hooding’, where a bird of prey covers a captured prey item. But it makes sense that it could help a youngster avoid detection from predators.
The “Wood Thrushes” in the video actually are Song Sparrows (Melospiza melodia).
I stand corrected, not yet a proper birder. Thank you.
I’d agree with the main suggestion by the authors. The proning behavior of the cooper’s hawk suggests to me lowering the profile to escape detection. The adult in the image above may be keeping an eye out for predators and signaling danger. Just as fawns sink low in the grass until mamma gives the OK.
I am pretty sure they are sunning themselves, note the adult also getting into the act and note they are in a sunny patch. Note their tail feathers are fully spread; if they are trying to hide they are doing it wrong!
Perhaps, but I suspect the air temperature is fairly high. No need to bask. Also, remember, the predator would most likely be viewing this scene from some distance at just above ground level – a coyote or fox. From there these chicks should be out of site.
It’s not for heating, birds sun themselves like that to kill parasites and fungal diseases. It is a very common behavior. If they were worried about predators they’d get off the ground and also move into the shadows.
Interesting photos, I have not observed proning outside of the nest. I have heard of young deer doing this when they get frightened on the road and someone has carried it off to the side so it wouldn’t get hit.
See my comments above; I am pretty sure this is sunning behavior.
I had no idea hawks might lie parallel to a branch, like a nighthawk.
Stephen,
Great shot of the waxwing! How close did you get and HOW did you get that close?