If not for a dusk shower on Tuesday evening, just as we were
closing nets, the VCE team could have boasted a second consecutive week
of dry weather on Mt. Mansfield. Regardless, we enjoyed the best overall
conditions of our field season so far, with nearly calm winds, warm
temperatures, variable cloud cover, and sparse black flies. A contingent
of 9 that included staff, summer field interns and interested visitors
had our 24 nets open by 7:30 pm and captured 7 birds by nightfall. The
dusk chorus was -- as is typical in mid-July -- much reduced from a
month ago, with half-hearted singing by Bicknell's and Swainson's
thrushes and White-throated Sparrows. American Robins and Winter Wrens,
some of which likely have second nests, were the only robust songsters.
We
had our nets reopened by 4:30 am, and the dawn chorus showed about the
same vigor that it had 8 hours earlier (i.e., not much). Netting
activity was steady, if not fast-paced, and we captured a total of 39
birds by the time we closed up shop at 11:00 am. Highlights included the
season's first Winter Wren (we're always incredulous at how tiny these
birds are, especially given the volume of their song...) and Magnolia
Warbler, and free-flying juveniles of 3 species. Bicknell's Thrush
(BITH) took numeric honors, with 13 birds captured (7 females, 6 males).
Interestingly, we did not capture a single Swainson's Thrush, though an
active nest with 4 chicks not far from our banding "station" in the
upper parking lot should fledge any day.
Our capture totals:
Downy Woodpecker 1 free-flying bird in juvenal plumage
Winter Wren 1 female with fully-developed brood patch indicating a nest with eggs or very young chicks
Bicknell's Thrush 13 all 7 females with regressing brood patches; 11
within-season or between-year recaptures, 2 new yearling females
American Robin 1 adult male
Magnolia Warbler 1 yearling male
Blackpoll Warbler 8 5 males, 3 females with full or regressing brood patches; 3
new birds and 5 within-season or between-year recaptures
Yellow-rumped Warbler (Myrtle) 3 1 free-flying juvenile, 2 recaptured males banded in June 2016
Dark-eyed Junco (Slate-colored) 4 all free-flying juveniles
White-throated Sparrow 7 all males ; 5 new, 2 recaptures from previous years (1 banded in June 2015, 1 in June 2016)
View this checklist online at
http://ebird.org/ebird/view/checklist/S38122082For
context with recent years, we've so far captured 29 BITH this season
(28 by this date last summer, 35 in 2015, 41 in 2014). What's especially
interesting is that only 9 of these 2017 birds have been new captures
(i.e., previously unbanded), while the other 20 were recaptures of birds
banded between 2011 and 2016. We've so far captured four 7 seven-year
BITH, one 6 year-old bird, and several 2-3 year-old birds,. Two males
have been captured at least once in every summer since 2011, while
several other returns have been missed in one or more summers since we
originally banded them. One 7 year-old female recaptured this June had
only been encountered twice before -- once when we banded her on 11
September 2011 and again on 16 September 2015 (in neither of those years
did we know her sex, as she wasn't in breeding condition then)!
Below
are BITH capture totals as of 12 July for the past four years. We were
rained out of the second and third weeks this June and so missed two of
the most critical weeks of our field season for captures.
|
Male
|
Female
|
|
New
|
Return
|
Total
|
New
|
Return
|
Total
|
2017
|
4
|
13
|
17
|
5
|
7
|
12
|
2016
|
8
|
13
|
21
|
4
|
3
|
7
|
2015
|
9
|
12
|
21
|
7
|
7
|
14
|
2014
|
17
|
11
|
28
|
8
|
5
|
13
|
Without going into quite the same level of
detail for Swainson's Thrush (SWTH) and Blackpoll Warbler (BLPW), here
are total numbers as of 12 July for 2014-2017:
|
2017
|
2016
|
2015
|
2014
|
SWTH male
|
6
|
16
|
9
|
14
|
SWTH female
|
1
|
2
|
1
|
4
|
SWTH total
|
7
|
18
|
10
|
18
|
BLPW male
|
11
|
25
|
12
|
21
|
BLPW female
|
8
|
10
|
12
|
7
|
BLPW total
|
19
|
35
|
24
|
28
|
These
are just "raw" numbers, so they don't mean a great deal without
accounting for our netting effort and other variables, but they're fun
to ponder. I'll provide a final 2014-17 tally after we wrap up our
summer field season at the end of this month.
Never a dull moment on Mansfield...
Chris
________________________
Chris Rimmer
Vermont Center for Ecostudies
PO Box 420 | Norwich, Vermont 05055
802.649.1431 x202
http://vtecostudies.org/