Wednesday, February 27, 2013

Downy Woodpecker

This female Downy Woodpecker fed at our suet feeder. If you look closely, you may notice that this bird is banded on her left foot, so she is probably one of my local birds. I took this photo because the woodpecker, with her bill pointed skyward, seemed frozen at the feeder. I have noted this behavior when predators are nearby. Curiously this strategy is not mentioned in Jackson and Ouellet’s (2002) definitive account of this species.

As I write this post, I am surprised by this woodpecker’s white nape. Previously I posted rhapsodically on the beauty of female Downy Woodpeckers—compare the black nape on the nape of the woodpecker at this link with the white nape on the present bird. None of my field guides show woodpeckers from behind. Clearly my identification is correct, the bill of the bird on the present post is too small to belong to a Hairy Woodpecker (which my guides also show with a black nape).

Jackson and Ouellet’s (2002) list a number of hypotheses for the Downy’s plumage patterns. They do not mention the possibility that the two spots on the upper back may act as cryptic eye spots, making a predator think the woodpecker is facing it. To me, this Downy’s back looks a bit like a face. Another unmentioned possibility is that the white stripe down the back camouflages these small woodpeckers as they climb about snow-spattered trees.

P.S. I received the following comments from Jerry Jackson: "While working on my dissertation eons ago, I examined and measured about 6000 Downy Woodpeckers -- presumably about half of those were females.  There is considerable variation in the extent of white on the nape.  The complete band is relatively common and a characteristic that is also variable in Hairy Woodpeckers.  As an aside, in Hairy males, birds in eastern North America can have either a complete band of red or a red spot on each side of the nape.  In western North America, males seem to invariably have a solid red band across the nape -- and that band is wider (anterior-posterior) than in birds from the east. 

"I think your idea about the eyespots is on target.  I've been doing a lot of work with eyespots lately and certainly this was one of the first birds I had noted. The "freezing" and "sky-pointing" in response to the presence of a potential predator (or an alarm call given by another bird) is common. While I failed to mention it, I believe it is in the literature."

1 comment:

  1. Interesting actions from the Downy--"frozen at the feeder"

    I will need to watch for that