American Woodcock
Cornell Lab of Ornithology, Wilson Trail - 6 April 2008
This amazingly cooperative individual was first found by Mark Chao along the Wilson Trail behind theCornell Lab of Ornithology, on 3 April, and remained for at least a few more days in the exact same spot
where it was observed by many. Below are a few photos and some video of the "rocking" behavior seen in
this species - behavior similar to the "tail bobbing" of Spotted Sandpipers, and very similar to behavior I
have seen in Wilson's Snipe (for video, click here). Some believe this behavior is a foraging behavior that has
become an innate response to stress. Some discussion of this behavior can be found in the following article:
"Marshal, W.H. 1982. Does the Woodcock Bob or Rock: And Why?," The Auk 99(4), pp. 791-792.
However, I'm not quite convinced. My pet hypothesis? It may perhaps facilatate respiration (?). A friend
of mine (Sarah States) were talking and we came up with another: perhaps the constant motion masks any
vibrations that food items would take as a signal that there is a predator around. This doesn't explain
why they seem to be rocking almost constantly (feeding or not), but seems reasonable. Alas, perhaps
someone will one day resolve the matter (got a woodcock-sized respirometer!?). Until then, let the hypotheses fly!
~~~ Video of the rocking behavior is at the bottom of the page. ~~~
Video of the "rocking"
From around 3 hours of observation, it appeared the rocking behavior was not closely associated with foraging/feeding.It seemed pretty much whenever the bird was awake and not being disturbed (e.g. when acting alert to observers, etc.)
it was rocking. It would also rock while probing the ground for worms (of which it found many), often pausing
when it's bill was deep in the ground, which is consistent with the bill being a sensory tool for detecting worms, etc.
For comparison, you may also be interested comparing these to similar behavior seen in this video of a Wilson's Snipe.
- Video #1: Rocking behavior while walking, moments after waking up.
Note: Best with Missy Elliot's "Work It" as the audio!
- Video #2: Next, the "alert" posture after being disturbed from a nap.
- Video #3: Lastly, some more video of the bird foraging and feeding.