VCE's final summer field session on Mt. Mansfield Tuesday evening 
started on a rough note, as a torrential downpour caught us off-guard 
while we were out setting mist nets.  However, we gradually dried out 
with the steadily improving weather, and yesterday morning was 
productive.  Most montane forest nests have clearly hatched, if not 
fledged, and vocal activity of all species was more pronounced than 
during the previous 2-3 weeks.  We mist-netted or observed fledglings of 
Blackpoll and Yellow-rumped warbler, Dark-eyed Junco, White-throated 
Sparrow, and American Robin.  We were surprised to capture 4 juvenile 
and apparently independent Hermit Thrushes, which do not breed on the 
ridgeline.  Other mist net captures included 11 Bicknell's Thrushes -- 4 
unbanded males, 6 birds that we had already captured earlier in the 
season, and one 6 year-old male with a solar geolocator that had managed 
to elude us all summer.

In addition to free-flying juveniles, signs that the avian nesting 
season is waning included several females of different species with 
regressing brood/incubation patches, and a number of adult birds in the 
early stages of flight feather molt.  Most migrant songbirds fit their 
annual molt (an energy-intensive undertaking) between the end of 
breeding and departure for fall migration, so finding thrushes and 
warblers with their innermost primaries missing is a sure sign of things 
to come.  By the end of this month, the montane forest will be a quiet 
place, as vocalizing becomes scarce and adults lay low while in heavy molt.

We'll make a final foray to Mansfield in early to mid-September, when 
Bicknell's Thrushes typically show a brief resurgence of activity, 
including calling and singing, before they head south later in the month 
or during early October.

Chris

-- 
Chris Rimmer
Vermont Center for Ecostudies
P.O. Box 420
Norwich, VT 05055
802-649-1431 ext. 1
http://www.vtecostudies.org