Wednesday, December 10, 2008

A harlequin and a puzzling grebe

This afternoon the sun broke free from the clouds and I made a casual run to the St Joseph beaches with a very modest goal of just finding some Herring gulls to photograph in the sun for once.  Well, I did find a few photo-worthy birds, but at Silver Beach I found a good number of birds sheltering from the mild north winds on the leeward side of the southern pier.

In front of a flock of buffleheads was this smartly-marked duck, no ID problem here:
It's a male harlequin duck with the crisp crescent in front of the eye, white ear patch, and a subtler vertical whitish mark on the neck.  In the very best of lights it did have some bluish gloss.  It didn't have any other white on it, none on the body.  I thought it was probably a first year bird given that it lacks the whitish marks in the tertials that Sibley shows a full winter-plumaged male as having.

There was also a small dark grebe.  My initial reaction when I first saw it was that it was an eared grebe.  With closer study it wasn't holding up that well.  I had called Tim after I got a few shots of the duck and he asked me if there was an eared grebe there too.  He'd seen the duck that morning and seen a/the grebe last night.  Before we could talk further a fisherman appeared behind me and I hung up to try to get photos before the birds were pushed farther out and we didn't talk about it at any length.  I don't know for sure that this is the same bird.

First is my best overall pic of the bird; it was difficult to get a good front-lit photo because of the configuration of the pier and the southern winter sun.  The bird has a dark face.  A typical horned grebe has a very crisp dark gray crown and white cheek and throat.  Per Sibley either species should be in full winter plumage by now, and certainly I can't remember seeing anything but that plumage in horned grebe this time of year.

There are structural clues; an eared grebe typically has the peak of the crown in front of or about even with the eye, in horned this is farther back on the head.  The eared has a thinner and upturned bill.  Horned does have a pale tip to the bill though this can be hard to see and either could probably show it if backlit enough.

The next 2 pics show the head shape, eared has a more peaked crown than horned, this is one of very few birds where looking at the bird as it is going away from you is actually quite helpful.

Another side view of the bird, probably the sharpest of the bill shape (I had to play with the contrast and brightness of this one as it was underexposed)

Here's a composite of my 4 best side views of the head (ignore the one random gray line) followed by old photos I've taken of the two species (eared on the left, horned on the right obviously):

I think the bill of today's bird is thicker than any eared grebe I've ever seen; the maxilla appears convex rather than concave.  I got the suggestion of a pale tip, though again that could be artifactual due to the lighting conditions.  The head seemed to peak behind the eye, but seemed rounder than the typical horned.  I don't know if a first year eared grebe would have a thicker, less up-turned bill than an older one would; Sibley does not show that however.  The other thing to think about on this bird is that the longer I watched it, the more I seemed to see the left leg.  I wonder what a horned grebe would look like that couldn't preen its cheek and chin; I suspect that it would look a great deal like the bird today.

If you go to look for these birds, BE CAREFUL on the pier.  It's covered in ice.  Despite being really careful on the way back, I took a fall and banged the scope down hard (thank goodness it seemed to be unaffected).  I continued to the beach to try photos from a different angle and wondered why my fingers were sticking to the camera, they've never frosted down before.  I looked down and saw my fingers all bloody, I took a picture but decided to spare you the image.

1 comment:

col said...

looks good for slavonian/horned to me - head shape & bill wrong for black-necked/eared