Through the first nine days of the
month, 2,500 net hours of effort resulted in our banding a total of 646
birds of 60 species (26 birds per 100 net-hours); an additional 122 recaptures
were processed. The best day was 8
May, when 122 birds of 35 species were banded;
the capture rate of 30.5 birds/100 net-hours that day also is the highest
recorded during the period. Top ten species so far in May are American
Goldfinch (59 banded), Gray Catbird (58), Ruby-crowned Kinglet (46), Yellow
Warbler (44), Rose-breasted Grosbeak (28), Common Yellowthroat (26), Swamp
Sparrow (25), Blue Jay (23), White-throated Sparrow (22) and Nashville
Warbler (21).
For their help with the banding
in early May, many thanks go to volunteers Mary Shidel, Molly McDermott,
Matt Shumar, Brent Worls, Lauren Schneider, Dean Thompson, Margaret Hahn,
visiting bander Bruce Steger, Sara Sargent, Danilo Mejia, and Maria Paulino.
In the photos below, a male Golden-winged
Warbler, banded on 3 May
(top photo) and a male Blue-winged Warbler banded on 2
May (bottom photo) nicely frame the hybrid
GWWA X BWWA male "Brewster's" Warbler (middle photo) banded at the end
of April. See also April
highlights.
Almost as rare as the hybrid Vermivora
above, especially in spring, is this ASY female Orange-crowned Warbler
(Vermivora celata) banded on 8 May.
This species was comletely absent from our spring 2006 totals.
On 6
May, we banded this adult male Canada Warbler.
When ageing warblers, in general, we look for a molt limit among the carpal
and greater alula covert (also referred to as A1). However, birds
with bluish-gray or greenish plumage tend to show much less obvious contrast
in color, lustre, and wear between the retained juvenal and molted wing
feathers. To further complicate things, worn adult feathers can look
quite dull and brownish, especially in this species. Fortunately,
CAWAs are also a bit more unusual in that body plumage is rather distinguishable
between the age/sex classes, particularly in the spring. As is the
case with this bird, ASY males have the most extensive black in the face
and heaviest black breast streaking. (click
here for comparison photos and more explanation of the other age/sex
classes of Canada Warblers).
While you can get a good intial
impression of the age/sex of a bird based on outward plumage, remember,
it is always best to verify that impression with a careful examination
of the wing for molt limits!
This ASY female Orchard Oriole was
a "good get" for us as the long term average for this species in the spring
is < 1.
While it is an invasive weed, it
grows principally in lawns and therefore does not compete with many other
native plant species. We enjoy the brightness that dandelions add
to the lawn here at Powdermill and never spray pesticides to be rid of
them. But few also realize what a wonderful food source and attractant
dandelions are to the many birds we enjoy observing during spring migration.
This White-crowned Sparrow, banded on 1 May,
is
proof positive that this bird, like many others, feed extensively on dandelions
that are just setting seed this time of year. The "dirt" on the bird's
beak is actually dandelion "latex" and we see this frequently on many other
species as well, including, American Goldfinch, Chipping Sparrow, and Field
Sparrow.
Because they are only rarely banded
at Powdermill, where little or no suitable grassland habitat for them exists,
Savannah Sparrows are always something of a surprise, albeit a pleasant
one! The photo of the bird's spread wing shows a comparatively unextensive
first prebasic molt, including only the lesser, median, and greater coverts
of the wing, plus the carpal covert, making the age a clear SY.
Rose-breasted Grosbeaks arrived
to the banding area in large numbers this week and, already we've banded
more than double the number we had by this time last year.
Among them was this unusual ASY
female, who apparently had replaced a few greater coverts and one primary
covert during her definitive prealternate molt. The replaced primary
covert, in particular, is very black with a large white spot, like we might
expect to see on a male RBGR.
