Andy,
I work as an owl surveyor in the Oregon Cascades and am often in good Sooty
Grouse habitat in the evenings. I have heard the same thing you observed
many times - grouse continuing to boom after sunset. They seem to, on the
whole, begin to quiet down around sunset but some individuals will persist
an hour or two after dark. I have never heard one carrying on any later
than that.
The first time I heard one booming at night it really confused me. I
reached for my compass to gather an azimuth on the sound thinking I had
detected some kind of owl. Didn't take long to figure out but it struck me
as an odd behavior too.
Cody Smith
Corvallis, OR
On Tuesday, May 31, 2016, Andy Frank <andydfrank@xxxxxxxxx> wrote:
Though this happened in Washington and not Oregon, I assume the behavior
likely also occurs here and thought others might find this of interest. I
had camped at Climber's Bivouac at 3750' elevation last night; this is at
the base of Mt Saint Helens. A SOOTY GROUSE was calling intermittently in
the late afternoon, but then much more frequently as dusk approached. What
amazed me was it kept calling until 9:29PM though sunset was more than 35
minutes earlier. And then this morning it started calling at 4:20AM, more
than a full hour before sunrise.
I had not previously camped in Sooty Grouse habitat this time of year and
instead had only heard them at more "regular" hours mid-day. I found it
fascinating that this bird was so persistent and advertised during such
extended hours.
Also a treat were all the Hermit Thrushes and Varied Thrushes that were
quiet late afternoon, but were all singing towards dusk, and the 2 Gray
Jays that found our breakfast this morning so tempting.
Andy Frank
