[CT Birds] mystery bird in Guilford

Greg Hanisek ghanisek at rep-am.com
Tue Nov 6 22:24:42 EST 2012

Given Amy's nice series of pictures I think it's quite clear that this bird 
is a juvenile Cooper's Hawk:
It lacks the bulk and powerful look of N Goshawk, which approaches a 
Red-tailed Hawk in size. Its very lightly streaked belly and clear undertail 
coverts differ from the heavy streaking Gos shows in this area; its has a 
short, weak supercillium compared to the more prominent one of N Gos; the 
white back mottling is fine for Cooper's, but the bird pictured lacks the 
boldly checkered appearance usually shown on the back of a Gos..

In more general terms, Gos is a shy forest bird (except when someone 
approaches its nest); Coop is a bold suburban feeder-raider. It's certainly 
not impossible to have a Gos show up in your yard but Coop is much, much 
more likely.

Juv. Gos is probably one of the most misidentified birds in places where it 
occurs. Actually, to be more accurate, large female Cooper's Hawks and imm 
Red-shouldered Hawks are often misidentified as Goshawks. I've even see a 
photo of Red-tailed eatig a gull that was called a Gos. One problem is that 
all of those species can show a supercillium, which is the probably the 
best-known Goshawk field mark. It's a good example why single field marks 
are seldom, if ever, good things to hang an ID on.

Voting for IDs probably isn't the right term, since there's a right and 
wrong answer.

Greg Hanisek

----- Original Message ----- 
From: "Amy Hopkins" <hopkinsus at cs.com>
To: <ctbirds at lists.ctbirding.org>
Sent: Tuesday, November 06, 2012 9:35 PM
Subject: [CT Birds] mystery bird in Guilford

> This accipiter was terrorizing my backyard birds yesterday.  It's clearly 
> a juvenile, but the question is whether it's a juvie Cooper's hawk or 
> goshawk.  I've shown it to a few birders, and it's evenly split in the 
> "polls".  Note the white supercilium and speckled back, making me lean 
> towards goshawk.  But the brown belly streaks don't go completely down, 
> like a Cooper's.  Maybe or maybe not zig-zag banding on tail. 
> Unfortunately in the frontal views, the tail is obscured by a UV sticker 
> used to keep birds from smacking into the glass (all photos taken through 
> glass).
> The front of the birdhouse is 8" tall and the back 14".
> http://s995.beta.photobucket.com/user/galahmom/library/other%20photos/mystery%20bird
> I keep old Christmas trees in the backyward to provide shelter to the 
> little birds.  This bird pounced down on one of them and was trying to 
> pull the little hiding birds out!
> Let the voting begin!
> Amy Hopkins
> Guilford
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