Our banding capture rate for this week was >50 birds/100 net-hrs., our highest capture rate since late April.  The largest number of birds caught continues to be young-of-the-year (hatching year, or HY, in banding terminology) produced by the more common breeding residents in and around the banding area:  Gray Catbird, Song Sparrow, American Redstart, and Hooded Warbler.  Increasingly, however, early fall migrants are adding into our weekly banding list.  One of the Yellow Warblers this week scored a maximum "3" fat on our 0-3 scale, and another scored a "2."  The two Northern Waterthrushes banded on the last day of this week (the first ones banded since June 1) also were migrants with visible fat deposits.

We have just begun to catch our first HY Cedar Waxwings (photo below right) and, as usual, many of them are sporting orange, rather than yellow, tail bands.  This phenomenon, which we have published on  (Evidence supporting a dietary basis for orange-tipped rectrices in the Cedar Waxwing.  1992.  Journal of Field Ornithology 63:212-216), occurs when nestling CEDWs are fed large quantities of Tartarian honeysuckle berries (seen in the background of the photo) while their juvenal tail feathers are developing.   A red pigment in the berries, rhodoxanthin, is molecularly very similar to the carotenoid pigments responsible for yellow plumage and it apparently is deposited unmodified in the growing feathers along with the normal yellow pigments.  Because of this mixing of red and yellow pigments, young waxwings can have anything from plain yellow to light yellowish-orange to dark orange-red tail bands.

At least in southwestern Pennsylvania, the berries of this introduced but extensively naturalized honeysuckle are available only from about mid-June to early August, after which any uneaten berries have usually shriveled up.  For this reason the orange tail plumage variation is almost entirely restricted to juveniles here--adults normally undergo their molt after September, when the honeysuckle berries are no longer available in any quantity and many  fruits without rhodoxanthin are.  Interestlingly, adult that lose tail feathers accidentally and regrow them at this time of the year will often have an orange tip on the replacement feather(s).
 

The Powdermill fall banding season will begin officially on August 1, but that doesn't mean that it's too early for a confusing fall warbler or two!  See if you know this one caught today. Click here for the answer.