At 01:35 PM 2/26/98 -0800, Rob Saecker wrote:

>So I assume your following comments regarding frequency were for
>broad-wings, and not red-shoulders.

Yes.

> It got me interested enough to dig up
>my records from the GGRO (San Francisco hawk watch);

I trapped a red-tail there once...

> I only have 84-90 data
>on hand, but it shows RSHA as regular there, as one would expect. Low count
>of 104 in '85, high of 194 in '87.

Yes, as they nest along the northern coast.

> BWHA has a low count of 9, in '84, but a
>high in '90 of 153, a year in which the RSHA count was 155.

Since HawkWatch has begun monitoring at a couple of sites in the PNW,
BWHAs have been observed in passage, though only in very low numbers
(one or two birds a season).

>Some of the difference would be attributable, I think, to better i.d.
>skills of the watchers, and to better coverage (more watchers); '84 was the
>first year of the official GGRO count, I believe. But that wouldn't explain
>all of the difference. Interesting as it is, but it will be even more
>interesting to follow these numbers for another twenty or thirty years, to
>see where they go.

The GGRO count suffers from being held at a site where raptors hang out,
rather than simply pass by, as is the case at ridge counts. Our (HawkWatch)
site at Cape Flattery suffers the same problem. This makes interpretation of
the data much more difficult.



- Don Baccus, Portland OR <dhogaza at pacifier.com>
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