Subject: Northern Goshawk - 2 species?
Date: Apr 4 14:17:47 1995
From: "Gross, Eric {co-op}" - EGROSS at fwhdept.env.gov.bc.ca



Hi Tweeters, I am posting this on behalf of Tom Either........

As part of my graduate work I am conducting a review of all the subspecies
of Accipiter gentilis. I have thus far leaned heavily on Brown and Amadon
(1968), supplemented with some taxonomic work recently done here in North
America. I have used the taxonomic software program DELTA to facilitate this
review and to build a key for the subspecies identification. Now I am no
expert in this program or in classification but it struck me during this
process that Accipiter gentilis should be split into two species. Brown and
Amadon suggested that the lumping of the two forms into one species by the
AOU in 1957 constituted a mistake and I concur.

The argument is based on differences in plumage characteristics and
behavioral ecology. The North American goshawks are slate blue-grey above
with light grey-blue and black flecking on the underparts, a more prominent
eyestripe and red to crimson red eye. The eurasian goshawk is overall brown
on the upperparts with strong dark brown barring on the underparts; the eye
is yellow-orange.

Seemingly irreconcilable differences about the difference in the ecology
also point to a separation. Goshawks in Europe apparently do well in managed
forests and active logging areas. In North America, especially in the west
where most of the work is being conducted , goshawks are declining due in
large part to logging in foraging and nesting areas. This discrepancy is
often exlained as a difference in any number of potentially biasing factors
between studies such as techniques, habitat, competitors, prey base, etc..
Could a more reasonable and satisfactory explanation be that we are dealing
with two different species?

If you have comments, or information that could enlighten me on this problem
please either respond to this list or to me directly ( as I am not yet a
subscriber - but will be as soon as I finish this message) and I will
summarize the info and repost. If you want to forward this message please do

so.

Thanks

Tom Ethier
Victoria BC
tethier at fwhdept.env.gov.bc.ca

.......This has also been crossposted to consbio and bene listservers so I
apologize for duplication.
If you are on any other listservers, please feel free to crosspost this
message.
Thanks in advance, and if you cannot contact Tom please try me,

Eric Gross
egross at fwhdept.env.gov.bc.ca
Victoria BC Canada