anomalous Eared Grebe (1 Viewer)

I videoed this grebe today (well, yesterday). What intrigued me at the time is that I hadn't seen this particular diving behavior before; normally when a grebe dives, I can't see it or track it at all until it surfaces somewhere else, seemingly randomly. But this grebe was diving in shallow water and I was able to follow the flurry of water and catch the grebe on camera the moment it surfaced. There was lots of vegetable matter which was the grebe was getting caught in and repeatedly having to shake off.

I did not notice the anomaly until I looked at the still photos (I haven't transferred the video yet). It sure looks like an Eared Grebe in most respects (and I assumed the same while I was filming it), but it has distinct white spots over its lores like a Horned Grebe. The bizarre thing is that these spots are very dull looking from a sideways view, almost black, but when the grebe angles forward they became bright. In an Eared Grebe photo search I have only either seen no spots or very dull spots.

Is this in fact an Eared Grebe? If so how can the spots be explained? The location is San Pedro, California.

I think it's Eared Grebe.As I know,that spot sometimes does appear on an Eared Grebe.

Hi David,

It's definitely Eared Grebe, not really sure what the spots doing there, don't think it's that significant though.

D

Thanks mcaribou and Dan.

Any idea if the spots are rare? The fact that I haven't found any photos that show them would seem to suggest they are, but perhaps there is a skew in the Eared Grebe photos that people choose to post. Although I'd think the skew would be in the direction of posting more of grebes with the spots! I think they're quite handsome.

I'm also curious about the physical reason behind the spots being dark gray from one angle and bright white from another. What other birds have plumage like this?

Today, again I saw at least one individual (maybe the same one!) with this characteristic. The grebe came very close (it's striking how small an Eared Grebe is!) and I got a better photo:

David Ellsworth said:

Thanks mcaribou and Dan.

Any idea if the spots are rare? The fact that I haven't found any photos that show them would seem to suggest they are, but perhaps there is a skew in the Eared Grebe photos that people choose to post. Although I'd think the skew would be in the direction of posting more of grebes with the spots! I think they're quite handsome.

I'm also curious about the physical reason behind the spots being dark gray from one angle and bright white from another. What other birds have plumage like this?

Today, again I saw at least one individual (maybe the same one!) with this characteristic. The grebe came very close (it's striking how small an Eared Grebe is!) and I got a better photo:

Click to expand...

Hi David,

I cannot really answer exactly what is going on with the loral spots, but I would say that it seems to be a variable feature of birds in winter and first winter feathering. Doing a Google image search yields others with the same feature to varying degrees, e.g.:

http://homepage.mac.com/rstacy/ images/pages/grebes/eared/2001/110201B13.html
http://www.schmoker.org/BirdPics/Photos/LoonsGrebes/EAGRpath.jpg
http://www.petalumawetlandspark.org/HTML/EaredGrebe2.html
http://fp2k.redshift.com/billhill/eared_grebe.htm
http://infohost.nmt.edu/~shipman/z/cbc/105/eargre1.jpg

Chris

Chris Benesh said:

Doing a Google image search yields others with the same feature to varying degrees

Click to expand...

Thanks Chris — nicely found. It looks to me like those birds may have the feature to the same degree as the one I saw, taking into account that it's most visible with the bill facing the observer. On the other hand, I found some more photos of Eared Grebes facing the observer, with spots, and it looks like the spots are not as bright:

http://f.hatena.ne.jp/images/fotolife/A/ACORN/20060210/20060210122821.jpg
http://www.pbase.com/dadas115/image/54960737
http://www.pbase.com/image/52919093

So it seems they may be variable overall. But the variations in photo quality and lack of many observer-facing photos are kind of frustrating. It's unclear how common the spots are and whether or not they're always angle-dependent. I wonder if there is any field guide that shows this variation.