Interesting discussion. Couple of points which will not be brief because I
struggle with brief.

1. This bird is not a Little Blue. I think most have agreed on this, but I
just wanted to reiterate the point. I base this on a couple of things.
While I am very hesitant to use words like "never" when it comes to
bare-part coloration of small white herons, I think it can safely be said
that Little Blues never (dangerous word!) shows sharply contrasting, bright
yellow facial skin. It is still developing and does not extend across the
entire lores, but it is present. All other "nevers" about bare-part
coloration in recently fledged herons will likely get you in trouble at
least some of the time. Bill color largely does not matter on very young
herons.
Also, I see a bit of a tuft on the nape. Not much of one, but first-year
Little Blues usually have smooth napes and, while it is often hidden, most
Snowy Egrets, both first-year and adults in winter, seem to be able to show
at least a hint of a tuft some of the time. So the presents of a tuft
indicates Snowy, the apparent lack of one indicates nothing.
Also the eyes of this bird are bright, clear lemon yellow. Little Blues of
all ages have irises that are just a touch cloudy or pale greenish.
I agree that the lack of gray on the primaries is a strong argument against
Little Blue. Though while I personally have never failed to see the gray
when I have looked for it, it can be very subtle and washed out on some
birds.
So while I believe Little Blue can be positively eliminated, I'm not
completely ready to say that it is definitely a Snowy.
2. Is there any evidence for Little Blue? I believe that the answer to this
is yes though some would view the evidence as circumstantial. Both Wilson
Cady and the Sullivan's have photos of the bird with its neck outstretched
and the head cocked downward. Little Blues do this all the time. I would
consider it to be their most common feeding posture. Snowy's stretch their
necks out like this usually only when disturbed and looking around. When
their heads are up their bills are usually held on the horizontal plane, not
cocked down. They very rarely feed with their necks outstretched for any
period of time. While they often feed actively as has been mentioned
already, when the feed slowly they keep changing the position of the head
and neck or leave them coiled. Typical feeding postures included bring the
head close to the water, drawing it back slowly, coil their neck, uncoil it,
and cock the head from side-to-side. They like to mix up these postures and
change them regularly. Usually the only time they hold it outstretched for
long is right before they make a strike. The fact that both Wilson Cady and
the Sullivan's have photos with the neck outstretched and seemingly frozen
is interesting.
The shape of the neck is also interesting. Notice that from the body to the
head, the neck of this bird tapers gradually, becoming thinnest near the
throat. While this is typical for Little Blue, in Snowy Egret the neck
tapers quickly and is parallel-sided and equally thin for most of its
length. Do a Google image search on Snowy Egret look for photos of birds
with their heads up, and you will see that this is true. When feeding these
species usually walk differently. Little Blue drag their feet, leaving them
in the water. Snowy is a high-stepper and, in all but the deepest water,
usually pulls their feet out of the water and steps back down. In the
Sullivan's photos it appears that this bird did a bit of both. As Alvaro
Jaramillo pointed out on ID-Frontiers, the shape of the bill probably isn't
much use because the bird is so young that the bill is still growing, so I
will ignore it. In my mind, this bird is likely from California. Little
Blue is scarce in most of CA, breeding in small numbers in the San Diego
area. This is exactly the kind of situation where hybridization is more
likely to occur. A Little Blue might not have been able to find a mate of
its own species and resorted to breeding with a Snowy. I am not saying that
this bird is a hybrid or even that I think that is a hybrid. I personally
think that it is probably a weird, likely sick, Snowy Egret. However I
cannot fully eliminate a hybrid so I've said all this to basically say
nothing. I don't know what the freaking thing is!

3. Finally- Dennis's statement copied below:

>Just think if birders expended the same amount of brain power trying to
>understand heron >coloration (why Little Blues change color with age,
>Reddish Egrets come in two color morphs, and >Great Blue Herons in certain
>areas of the Caribbean are white, while Great and Snowy Egrets don't >show
>such variation) as we did trying to figure out how to identify them.
>Wouldn't that kind of >understanding be great?

I take some exception to this statement. There is an underlying tone to it
that is condescending to birders. It is subtle and probably unintentional,
but it is still there. Statements like these make it difficult for birders
and academics/biologists to be friends and play nicely together. I can find
no reason why trying to work out the reasons behind color morphs or the lack
thereof in herons is morally superior or a better use of time than trying to
learn to identify them more accurately. There is still something to be
learned in either field. The difference is birders are much better suited
to contributing to identification than to researching color morphs in heron
or any such similar subject. The question of heron morphs is better left to
the realm of science. Researching such a subject would require vast amounts
of time and energy. Much more than most birders have to give. It would
require dropping virtually all other aspects of birds and concentrating on a
single set of subjects. In short, it sounds like a project for an ambitions
grad student.
In my opinion the constant evolution and refinement of bird identification
is a fascinating subject on par with studies of bird behavior, bird
intelligence, ect. All are driven by the desire to know more. There seems
to be a widely held, quiet belief among academics that any pursue labeled
"science" holds the moral high ground over all other pursuits. The
statement above seems to reflect that belief. It strikes me as neither
correct nor realistic. However, should a birder have an interest in
pursuing such a subject should receive the full backing of the birding and
scientific communities.

To illustrate my point about the value of birders and field identification,
I am copying an excerpt from something I received recently from Charlie
Wright. I hope you don't mind, Charlie!

>From Charlie:
[This weekend I watched a typical juv SemiSand (Semiplamated Sandpiper) at
extremely close range with 8 female Western Sandpipers. They flew around a
lot and the Semi could be readily picked out in flight by its relatively
smaller head and shorter neck. Admittedly, this was at much shorter
distances than most flight IDs would be made, so it's unlikely this is very
useful, however I thought it was interesting and warrants further
observation.]

I feel there is incredible value in the above statement and have a lot of
respect for people that make this kinds of observations while keeping them
in a realistic and useful context.

Respectfully,
Cameron Cox
Seattle, WA
Cameron_cox at hotmail.com