Hi Tweets,

Bob Norton writes:

>Besides the obvious orange of the DOUBLE-CRESTED CORMORANTS bill and
>gular pouch, the snake head of the PELAGIC CORMORANT, the BRANDT'S CORMORANT
>is hard to identify at any distance.
(snip)
>The forehead is much more steep in the BRANDT'S
>than the DOUBLE-CRESTED.

Agree. The ID problem is two-fold: on the water, Brandt's Cormorant (BRCO)
has about the same profile as Pelagic Cormorant (PECO), while when perched
on a buoy or rock, it's difficult to separate BRCO from Double-crested
Cormorant (DCCO) as they're the about the same size. Here's a number of
other features that can help to sort them out when they're too far out to
see gular pouch color or forecrown angle.

Perched or in flight, PECO always has the longest tail, BRCO obviously the
shortest, DCCO intermediate.

Perched together, BRCO and DCCO are the same size, while PECO is clearly
smaller than the other two, and an observer can compare tail lengths. The
slighter, dark bill of the BRCO may suggest PECO but this species has a
clearly thicker neck.

Away from its breeeding colonies, BRCO almost never perches close inshore,
at least in Vancouver BC, where instead of being a winter-only rarity as
local wisdom had it, they're actually fairly common on the offshore islands,
buoys and beacons of Burrard Inlet in autumn, winter and spring, and a
little further out in Georgia Strait in summer, but it's always a real
rarity along the shoreline.

In flight, BRCO is the bob-tailed hump-backed one with 'barn-door' wings,
and a neck held close to, sometimes below, the horizontal. PECO flies
likewise but its obviously long tail is the main ID mark and has a quicker
wingbeat. DCCO is *almost* always pretty easy as its flight profile is like
a landing-approach 747 in terminal flare, definitely heads-up and neck held
obviously above the horizontal; unlike the other two, it often has a crook
in its neck in flight.

A bird on the water is gonna be the toughest. Swimming, BRCO and PECO have
*very* similar profiles, both having small, comparatively rather
fragile-looking bills, but the thicker neck of BRCO is usually a good mark,
particularly when either comes up from a feeding dive and are still
sleeked-down. As usual, most of the ID problems are provided by the commoner
bird, in this case a lone PECO fairly well out from shore; is it a BRCO or
not? but just as usually, a BRCO is pretty clearly not the smaller species.
DCCO at distances of 500 meters or more often don't show the yellow color of
their bill/throat, but seem--not sure if this is just a personal perceptual
quirk or due to the gentler bill/forecrown angle pointed out by Bob--to have
a stouter bill than the other two at any distance.

Michael Price We aren't flying...we're falling with style!
Vancouver BC Canada -Buzz Lightyear, Toy Story
mprice at mindlink.net