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/ch
ecklist/S38122082

For 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/

<http://vtecostudies.org/>


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