February 98 Mystery Birds

My logs show that over 700 people visited this page last month, yet only 13 people voted on these birds.   The final tally was 11:2 in favor of Barrow's Goldeneye for the first (Lake Merritt) bird and 7:5 in favor of Common Goldeneye for the 2nd (San Francisco) bird.   The 2nd bird voting was particularly close with one person abstaining.  I believe it demonstrates the difficulty in applying some popular characters particularly in cases of only a single photo.  Click <here> to view the original quiz birds.

I agree with the majority on both birds.  Bird #1 is actually an immature male.   Note the small white spot emerging behind the bill.  On Common Goldeneye, this spot usually starts to appear just behind the bill and may produce a small crescent like Barrow's.  However, on Barrow's this crescent usually extends above the eye, on Common it does not.  Given that this is an immature male, I think it is odd in a number of respects.  The head shape is really not as large as I usually see on males; the color of the head has a reddish cast which is more typical of Common but this may be attributed to photographic effect.  The bill is rather pale which is a female character.  Male goldeneyes of all ages normally have all black bills.   So I think this is a very peculiar bird even though the species identification is fairly straightforward.  Note also the brown on the throat extending down slightly onto the foreneck which favors Barrow's.

Bird #2 seemed to cause the most difficulty.  The photo was cropped so it did not show the adult male Barrow's Goldeneye it associated with seen here. Despite the apparent guilt by Mixed pair of goldeneyes - SF, January 1978association, I feel reasonably confident that this bird is a Common Goldeneye.  The bill pattern of a narrow pale band behind the nail is not normally seen on Barrow's Goldeneyes on the West Coast.  The head shape and color seem to favor Barrow's, but I feel overall head shape is unreliable as more than an auxiliary identification clue and the color could be photographic artifact.  Head shape depends greatly on what the bird is doing and how the feathers are arranged.  The pattern of the "mane" on the back of the head is more reliable than forehead or crown.  In this photo that is difficult to assess, but I think it favors Common. I agree with those who argued that the bill shape favors Common.  One feature not mentioned by the voters is the white wing stripe on the side formed by the median wing coverts.  On adult female Common, this is white, on immatures and on Barrow's it's usually mottled gray.  Thus a female goldeneye with obviously white median coverts should be a Common, but one with gray medians could be either.  My interpretation of this photo is that it is a Common based on a combination of all characters.

I'd like to thank those of you who took the time to vote and provide comments. Not to embarrass anybody I have deleted the names from the comments.

The top photo appears to be a Barrow's based on the shape of the head (the fuller hindcrest makes the head look wider in profile) and the shape of the bill (the base is somewhat thicker than a Common would have). The scaliness of the scapulars looks odd to me, but I suppose it could be an effect of recent molt. The lower photo is a Common, despite the presence of some yellow in the bill tip: the bill base is thin, and the hindcrest is much less full than a Barrow's would be.

I would think the bill length and shape and head shape suggests a BAGO and specifically a young male. I think the SF bird is a COGO because of bill length and shape and bill/forecrown angle. All the facts will be shown by the record, and I am not a crook.

The bill shape and color of the Lake Merritt bird seems to be entirely consistent with Barrow's; what am I missing? As to the S.F. bird, I would say that it has the longer bill to depth at base ratio of a Common, and seems to have a bill pattern consistent with that species.

Bill size and shape; color where yellow; overall size (Barrow's always looks more compact to me, the same as eared:horned); on some the neatly cut-off, horizontal "d.a." is something I have seen only on Barrows. It seems (apart form the possibility of hybrids [but you wouldn't do that would you?]) that every bird you have shown is a Barrow's. I cannot make out the wing pattern in the flapping bird, though. I think that were these birds seen in the East, most knowledgeable observers would call them all Barrow's.

L. Merritt bird looks like a fairly conventional subadult or eclipse male BAGO in pre-definitive alternate molt. the SF goldeneye I'm going to *guess* on impression--crown's highest point is slightly forward of the eye--is an imm. female BAGO.

On the Lake Merritt bird, my simplistic reasoning is that the steep forehead, crown peaking in front of the eye, all light-colored bill, and not too massive a bill all point to Barrows. The San Francisco goldeneye looks very un-goldeneye-like in bill and head shape, but I believe the small bill is more fitting to Barrow's, early in the season before the color change.

On no. 1 bill seems short and head bulbous at rear. No. 2 looks less like a Barrow's to me, but I'm not sure. Angle may be deceiving.

For L. Merritt, head shape and bill within bounds. For SF head shape and bill not atypical for Common.

Lake Merritt bird has a slopey forehead whereas the SF bird has an almost vertical forehead

Just thought I better give a guess as your posting on BirdChat said not too many people were responding. my guess is based on the head shape and bill size of each bird.

I hope you won't use this information to embarrass me.

Immature female-plumage goldeneye. Immature female-plumage goldeneye photographed at Lake Merritt, Oakland California in October 1985 by Albert Ghiorso.  Perhaps a reasonable match for a controversial goldeneye photographed by Bill Hill, December 30, 1997 in Monterey County.
Mystery goldeneye And what is this?  Photographed in San Francisco in January 1978. If you think you know the answer to either or both of these, please fill out this feedback form. I will post a summary of the responses at the end of the month.

Page created February 3, 1998 and updated March 01, 1998 by Joe Morlan.
Photos copyright © Albert Ghiorso. All rights reserved