2003 Bird Lab updates - Ventana Wildlife Society

BSOL Update, March 2003:
March was a month of many beginnings and
endings. Spring began on March 21 (according to
the calendar). Winter rains are probably over and
the river won't rise again (not too much, that is).
The first Wilson's Warblers began arriving, and the
Hermit Thrushes, Ruby-crowned Kinglets, and
Myrtle Warblers are gearing up for northern
flights. Violet-green Swallows and Tree Swallows have returned and are
circling over the lab most of the day. Breeding morphology (cloacal
protuberances and brood patches) is beginning to show itself almost daily,
however, nest-building has been going on in earnest all month,
accompanied by much melodious singing by House Wrens, Purple
Finches, Wrentits, Song Sparrows, Wilson's Warblers, and
Orange-crowned Warblers.
Except for a few straggling "flyers" the monarch butterflies have left their
central California coast overwintering grounds (we are left with the
winter's data to analyze). They have been replaced by a multitude of
orange-tips, blues, whites, elfins, swallowtails, admirals, skippers, and
duskywings. California poppies are "popping" out everywhere. Western
fence lizards are doing their push-ups on the ground and up the walls.
Northward migrating gray whales may still be seen spouting water off
Molera Point. Summer fog is just beginning.
Mist-Netting and Banding
We had a total of 8 banding days in March, totaling 88
captures (26 species, up from each of the last 2 months)
for an average daily census of 11 captures. Hermit
Thrush was the most frequent species in our nets (20
captures), followed by Ruby-crowned Kinglet (10
captures, all females), Chestnut-backed Chickadee (8),
Wilson's Warbler (6, all males), and Myrtle Warbler
(5). On March 25, we banded our first Common
Yellowthroat of the season, a very colorful adult male. We hadn't captured
another Common Yellowthroat at the Andrew Molera State Park site since
last November 4.
We are pleased to note the observation of breeding morphology in a
California Thrasher male, two Chestnut-backed Chickadee females, and
two Spotted Towhee males. One of the Chestnut-backed Chickadees was
a recaptured female first banded here at BSOL last March 30: she also
showed a brood patch at the time of banding. Please note that last month
we may have missed reporting the momentous occasion of our very first
observation of the year of breeding morphology in a captured bird: on
February 25, we captured an adult female Bushtit with a brood patch.
Our first captures of Wilson's Warblers for the year were two birds on
March 18, and another four birds on March 24, all males. One of the