Subject: Re: Brief comments on the 1995 raptor migration at the Goshutes
Date: Oct 2 15:08:39 1995
From: Don Baccus - donb at Rational.COM


Scott Ray:

>I'm curious to learn whether you recaptured any birds that were banded in
>prior years or at other locals.

As of 20th September, we'd only had one recap of a previously banded
bird. We had no information on it at the time I left, but it looked
like it was probably one of ours (i.e. had a familiar prefix to the
band number, not that that's foolproof).

Unfortunately I forget what species, sex etc.

Last year we had roughly a dozen recaps, several of our own plus a
Kestrel I caught which was banded at the nest in the Jarbridge
Wilderness (near Jackpot, Nevada).

Since we catch nearly 25% of the observed migratory passage each
year, you'd think we'd get a lot more recaps. Several things work
against us:

1. Not many folks are banding accipiters and kestrels to the north
of us (or the south, for that matter).
2. In the fall, of course, the flight is heavily biased to kids that
will die over winter, thus won't be recapped in future years.
3. Kids are also easier to capture - they tend to be skinnier and
lighter than the adults, to some degree a result of their poor
hunting skills. Adults are more wary and less hungry.

On the other hand, our two projects in New Mexico (spring banding
in the Sandia mountains outside Albuquerque and fall banding in
the Monzano mountains) have a much higher percentage of recaps of
birds banded at those two sites. Indeed we have a couple of recaps
of birds banded in the spring in the Sandias being recaught in the
fall in the Monzanos - pretty amazing considering that only a couple
hundred migrants have been banded in our (sporadic) spring banding
in the Sandias.

So, a fourth possibility is that individual hawks use different routes
south in various years. This would be no surprise as our Wellsville
site (which borders the Great Salt Desert on the east, mirroring our
site on the west of this desert) gets a flight about 1/3 that of
the Goshutes - with a much higher percentage of adults, at least
when considering accipiters. Unfortunately we can't band at that
site to see if we'd get Goshutes recaps there (or Wellsvilles recaps
in the Goshutes) - logistics and the fact that the Wellsvilles site
lies within designated Wilderness and poor vegetation cover (for
blinds, mist-nets etc) have led us to reject the notion of banding
there. And, we know hawks use various other ranges near the Goshutes as well.
Access to the ridgetops of Great Basin ranges in general is poor, we're
fortunate to have only a 2 1/2 miles hike to the Goshutes site
(with a 2,000 ft. elevation gain however, starting at 7,000 feet to boot!).
The Wellsvilles site involves a 3 1/2 mile, 3,000 foot gain. There are a
bunch of interesting ranges such as the Deep Creek mountains in Utah directly
to the SE of our site, but access involves hiking several miles and of course
there is no water once you get there.


- Don Baccus, Portland OR <donb at rational.com>