The runaway highlight of this week's Mt. Mansfield field work was a
banded male Blackpoll Warbler, back on the ridgeline for a third
consecutive summer. This half-ounce songbird proved the champion
globe-trotter among 5 birds who yielded their solar geolocator data a
year ago. Read more on the VCE blog at
http://vtecostudies.org/blog/champion-blackpoll-globe-trotter-returns-to-mansfield/.
With only two weeks remaining in VCE's 2-month banding season on
Mansfield, Bicknell's Thrush numbers are about "normal", with 35
individuals so far captured. Of these, 19 are birds banded in previous
years (12 males, 7 females), while 16 are new birds (9 males, 7
females). Interestingly, female captures are high relative to our
long-term average, with males outnumbering females by 2.2:1. This
summer's ratio currently stands at 1.5 males per female. We don't read
much into this statistic, as it is based on one summer's data at a
single site on the landscape, but on the surface, it's encouraging.
Blackpoll mist net captures are slightly lower than at this point last
summer, 24 birds vs. 28 a year ago. Nine of these were previously banded
birds (7 males, 2 females), the other 15 new bandings (5 males, 10
females). This year's 1:1 sex ratio is a far cry from 2014's, when we
had captured 21 males and only 7 females at this stage of the field
season. Again, it's premature to draw conclusions, but we're somewhat
reassured to note equal numbers of males and females after two
consecutive years in which females were outnumbered >4:1 by males.
Swainson's Thrush numbers on the Mansfield ridgeline are notably lower
than in 2014, with 11 birds captured so far (9 males, 2 females) vs. 17
at this date last year (14 males, 3 females). This is a species that
appears to be moving upslope throughout the Northeast, yet I've heard
several observers comment this season that Swainson's numbers seem
reduced at higher elevations. It will be interesting to see what VCE's
2015 Mountain Birdwatch data reveal.
We had our first captures of free-flying juveniles on Mansfield this
week, including American Robins, Yellow-rumped Warblers, and Dark-eyed
Juncos. The most surprising bird of all was an adult female Least
Flycatcher, our first-ever capture of this species on the ridgeline over
24 years that included three fall migration periods (1995-1997).
Rarely a dull moment on the mountain...
Chris
--
Chris Rimmer
Vermont Center for Ecostudies
P.O. Box 420
Norwich, VT 05055
802-649-1431 ext. 1
www.vtecostudies.org
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