[obol] FW: Is it an eagle or what?

Tue Dec 4 11:39:16 PST 2007

Hi birders,

Interesting image. Looks like a subadult (2nd-3rd year) Bald Eagle to me.

It's easy to be confused by the degree of overexposure in this photo,
particularly the white-looking underside. Contrast level in direct sunlight
like this exceeds the latitude of most film and digital images, so lighter
areas look white and dusky areas look black (look at the treetrunk - the
left side appears white and the right almost black).

With that in mind, consider the possibilities. For starters, Ferruginous
Hawk and Osprey are both out of normal range this time of year at the
location mentioned (north of Stockton, California). It's usually best to try
to eliminate expected species first, rather than trying to make a bird into
something rare. In this case, Bald Eagle is more likely to occur at the
given location and season.

The bird is at a lake, which supports Bald Eagle or Osprey, both
water-loving species (Ferruginous Hawks like to hang around agricultural
fields and open areas).

Without getting into a lot of technical terms, it's massive, bulky, and
broad at the shoulders even when leaning forward. The head is squarish with
a noticeably large beak even when slightly turned toward the viewer. And
though coloration is tricky to see, there seems to be a mottled white line
across the wing, a mark on young Bald Eagles which is not present in most
other raptors. Who knows what color the washed-out underside is, though I
suspect it is mottled brown and white. There doesn't seem to be any strong
patterning on the head like you'd see on an Osprey, though again it's cast
in shadow and darker than life. And, again, without getting hung up on
individual field marks, my snap impression of overall size and shape is,
well, of a young Bald Eagle.

Take it, leave it, or list it ;)

Good birding,
Noah Strycker

On Dec 3, 2007 6:51 PM, Dan Gleason <dan-gleason at comcast.net> wrote:

> You can clearly see that the bird has a black bill and a yellow cere,
> which suggests a subadult Bald Eagle. …" Ferruginous hawks have a very
> apparent yellow bill…"
>
> I suggest that you look more closely at Ferruginous Hawks at your next
> opportunity. They have a dark bill and a yellow cere and these
> characteristics hold true for all ages and all morphs. (Read the species
> traits in Wheeler's Raptors of Western North America or other authorities).
> As you say, they do have a large gape but it cannot be clearly distinguished
> in this photo as to size. In no plumage does a Bald Eagle have this much
> clear white underneath. Young birds are very mottled not solid white.
> Adults, or near-adults are the only Bald Eagles with white heads and when
> the head is all white, the body is black. You suggest that Bald Eagles have
> "shorter tails that do not protrude beyond their wing tips." However, the
> photo seems to show a tail slightly longer than the wing tips and what can
> be seen of that tail is white, which again suggests Ferruginous Hawk.
>
> I am not saying that this is definitely a Ferruginous Hawk but that is my
> best guess based on what I can see. With the lighting conditions of this
> photo, it is hard to be sure of any ID with certainty. However, Ferruginous
> Hawk is consistent with everything I can see in this photo and many features
> are inconsistent with Bald Eagle.
>
> As eagles mature their bill gradually grows out from the cere.
>
> What do you mean by this? The cere is a dermal covering at the base of the
> bill that covers the nostrils of some birds (hawks, eagles, pigeons, some
> parrots). The bill does not grow out of the cere. The bill is well formed by
> the time the bird fledges. The *rhamphotheca* is the keratinized outer
> covering over the bone and makes what we see as the beak. The rhamphotheca
> grows throughout life in ALL birds. As birds eat and preen, the rhamphotheca
> is worn. This wear is replace by continual growth of the rhamphotheca. In
> some birds it, or portions of, are shed annually, as in puffins which have a
> very large rhamphotheca during the breeding season and a much smaller one in
> the winter. In Bald Eagles, the rhamphotheca and cere are both dark in
> juveniles.
>
> Bald Eagles have very large beaks at all ages and the beak on this bird
> looks too small in proportion to the head to be that of an eagle.
>
> An additional note about Golden Eagles: Their bill is NOT entirely yellow.
> To quote Wheeler: "The distal half of the bill is blackish and the basal
> half is pale blue." They do have a large yellow cere and fleshy gape.
>
>
> OBOL has generally been a safe and respectful place on which to offer help
> to others. I would request that you don't completely disregard the
> suggestions of others so blatantly in the future. Also, please look
> carefully at your "facts" as some of the things you say here are simply
> untrue or incomplete.
>
> Dan Gleason
>
> -------------
> Dan Gleason
> dan-gleason at comcast.net
> 541 345-0450
>
>
> On Dec 3, 2007, at 3:54 PM, Devon Batley wrote:
>
>
>
> ------------------------------
> From: devon_batley at hotmail.com
> To: kirkpat at charter.net
> Subject: RE: [obol] Is it an eagle or what?
> Date: Mon, 3 Dec 2007 23:54:15 +0000
>
>
> you can disregard both the suggestion of an Osprey or Ferruginous hawk.
> Though your friends' photo is washed out. You can clearly see that the bird
> has a black bill and a yellow cere, which suggests a subadult Bald Eagle. As
> eagles mature their bill gradually grows out from the cere. Conversely
> Golden Eagles have yellow bill from the get go. Ferruginous hawks have a
> very apparent yellow bill & cere w a large gape, visible from quite a
> distance. Also the head shape is wrong. While Ferruginous are large hawks
> they have a bulky chest which makes there head look small. The bird in this
> photo has a large protruding head. It is clearly not an Osprey as it has no
> eye stripe or brown necklace.
> Bald Eagles have large head and shorter tails that do not protrude beyond
> their wing tips. If you are still unsure consult the Wheeler Guide to
> Raptors of North America. This is the raptor identification bible.
>
>
>
>
>
>
> ------------------------------
> From: kirkpat at charter.net
> To: yaakovm at comcast.net; obol at lists.oregonstate.edu
> Date: Mon, 3 Dec 2007 14:20:56 -0800
> Subject: Re: [obol] Is it an eagle or what?
>
> How about Osprey.
>
> Doug Kirkpatrick
>
>  ------------------------------
> *From:* obol-bounces at lists.oregonstate.edu [
> mailto:obol-bounces at lists.oregonstate.edu<obol-bounces at lists.oregonstate.edu>]
> *On Behalf Of *Jordan Epstein
> *Sent:* Monday, December 03, 2007 1:04 PM
> *To:* obol at lists.oregonstate.edu
> *Subject:* [obol] Is it an eagle or what?
>
> To All On OBOL:
>
> A friend recently (mid-November) took this photo hiking near his house in
> Arnold, CA.  The photo was taken at Lake Alpine, which is about 100 miles
> northeast of Stockton.  He asked me what the bird was and I'm not sure.
> It's clearly a large raptor, probably an eagle.  But I wanted to share it
> with you to see if there were other possibilities.  The photo quality is not
> good so a clear identification might be difficult.  Any help would be
> appreciated.  The photo can be found at *
> http://share.shutterfly.com/action/welcome?sid=8BYs2rdq0bMKK*<http://share.shutterfly.com/action/welcome?sid=8BYs2rdq0bMKK&emid=sharshar&linkid=link5>
> .
>
> Jordan Epstein
>
> SW Portland
>
>
>
> ------------------------------
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