I ran into a little serendipity at the Stanwood Sewer Ponds on Sunday
morning the 17th in the form of a nice man from Nanaimo who was down here
visiting his mother in Arlington. Turns out he does bird censusing all day
long for environmental impact statements and such. He was a very good
teacher, and helped me add 3 species to my list for that location, which is
up to 115 now in the last year and a half. As we were hearing sparrows
singing, I mentioned that there had been talk of fall singing on Tweeters
recently. He immediately said "day length." So, Michael, there may be
something to your theory.

Dan Logen
Stanwood

----------
> From: Michael Hobbs <Hummer at isomedia.com>
> To: Tweeters <tweeters at u.washington.edu>
> Subject: Re: Ruffed Grouse?
> Date: Wednesday, October 20, 1999 10:51 AM
>
> I've been mulling these two messages (below) over, and I wonder if anyone
has
> looked at whether "gonadal recrudescence" is triggered by the fact that
the
> hours of daylight in October is the same as the hours of daylight in
March.
> Some birds may have a bit of a hair trigger and they start getting
excited
> inappropriately in fall. Those hypersexed birds may also react sooner
and
> stronger in spring. Thus, hyperreactivity to the stimulus may result in
both
> greater copulatory success in spring AND to gonadal recrudescence in
fall.
> Thus, fall sexual urges would only be correlated with spring success, not
> causal to that success. Thoughts?
>
> == Michael Hobbs
> == Kirkland WA
> == hummer at isomedia.com
>
>
> From: WAYNE WEBER <WAYNE_WEBER at bc.sympatico.ca>
>
>
> > For those of you who are not familiar with it, the phenomenon of
> > "gonadal recrudescence" is believed to be responsible for autumn
> > drumming by Ruffed Grouse and autumn singing by many other species.
> > Singing and other forms of courtship and territorial behavior are
> > dependent on high levels of androgens (male hormones). Unlike many
> > mammals, most male birds do not produce steady levels of male hormones
> > year-round. The gonads are large and active from early spring through
> > midsummer, but then they regress, and song and courtship behaviour
> > largely cease. However, in some species, under some conditions, there
> > is a partial recovery of the gonads for a while in the fall, and a
> > resumption of song (or drumming, in Ruffed Grouse), at least for a few
> > weeks. Sharp-tailed Grouse, for instance, are known to visit their
> > springtime leks (display grounds) during the fall.
>
> From: Gail Spitler <spitler at direct.ca>
>
> > I was about to send a comment that while I haven't heard Ruffed Grouse
> > drumming this autumn, our local Wild Turkeys are displaying. Again, not
with
> > the intensity seen in the spring, but it certainly looks like courtship
> > behavior (displaying, toms corralling the hens). Then I happened upon a
> > summary of an article in Avian Biology entitled Why do Black Grouse
perform
> > on lek sites outside the breeding season? It seems that the males who
> > possessed central lek locations in autumn had higher copulation success
the
> > following spring. The autumn behavior may provide the females with an
> > opportunity to assess males prior to the breeding season.
>
>
>
>