Fall 2005 Past Pictorial Highlights October 11-16

• 985 birds of 50 different species were banded this week; 26% of the week's catch were Yellow-rumped (Myrtle) Warblers (259 banded).  A total of 84 MYWA's on October 15th was our eleventh highest daily catch ever for the species.  The record high daily total for this species remains 187 banded on October 10, 1987.   Second most commonly banded bird this week was American Goldfinch (110), followed by White-throated Sparrow (89), Song Sparrow (61), Purple Finch (55), and Black-capped Chickadee (54), signalling a definite shift in species composition, especially toward the end of this week.  Our capture rates also picked up noticeably toward the end of the week from an average of 28 birds/100 net-hours for the first four days to 85/100 for the last two days.  In general, the fall migration season at Powdermill is characterized by high species diversity in the first two-thirds of the season (August through early October), with the largest number of birds coming in the final third of the season (after mid-October).  The turning point for this fall seems to have occurred at the end of this week.

• With two banding days totaling well over 200 and three others well over 100 birds, we were very thankful to have a lot of extra helping hands -  Hanna Mounce, Joe Schreiber, Randi Gerrish, Matt Clement, Jessica Maggio, Trish Miller, Pam Ferkett, Cokie Lindsay, David Norman, and Don and Amy Smith.

• This week, on Thursday, October 13, we bid farewell to David Norman, friend, visiting ringer, and Powdermill Research Associate from Great Britain, but not before netting one more new species for his visit and for our fall season.  David's 'guest-authored' web page from last week is a tough act to follow, and we thank him not only for that effort, but for all of his help with the banding over the course of the past month.  We thank him, too, for the beautiful photo of this adult female Eastern Bluebird (first of the season) banded on Thursday morning.

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• One of the 84 Yellow-rumped Warblers banded on October 15th was an adult female, surprisingly still undergoing her prebasic molt.  Note secondaries 5 and 6 (the two shorter brown feathers on the inside of the wing) have yet to even be replaced.  S3 and S4 (barely visible) were still in sheath (actively growing), along with tertial S7 and the outermost primaries.

• Our most diverse day was Wednesday, October 12 with 36 species of birds banded.

There are obvious differences between the HY male Cape May Warbler on the left and the HY female Cape May Warbler on the right (both banded on the 12th), but both sexes have characteristic streaks or stripes on their throat, upper breast, and sides, which is the source of the scientific species name for this Dendroica warbler, D. tigrina.



While adult male Scarlet Tanagers share the same yellow basic (winter) body plumage as HY males, ageing is a simple matter based on the retention of brown/yellow edged juvenal wing feathers.  In the case of this somewhat late HY male SCTA banded on October 15, three juvenal greater coverts are sandwiched between the outer and inner molted black greater coverts.  All the wing feathers on an adult male would be the uniform jet black color of the molted lesser and median coverts (the shoulder) and greater coverts on the bird in the photo above.  In such a case, birders could even easily make confident age determinations in the field.

• The HY Black-capped Chickadee below, banded on October 11th, was our first recorded bill deformity for the fall.  Bill aberrations have been documented in a wide range of species and are possibly caused by genetics or, during development, by injury, disease, and/or environmental contamination.  As many banders know, bill deformities are actually not all that uncommon, but their incidence can vary greatly from year to year.  The fall of 2003 was exceptional in this regard because of the unusually high incidence of bill deformities.  In the case of this chickadee, the upper mandible was elongated and crossed over the bottom.  That the bird could not feed efficiently with its malformed bill was evidenced by the fact that it had no visible fat deposits and weighed just 9.0g, which is very close to the minimum body mass ever recorded for a BCCH at Powdermill.

• A notable recapture this week was Black-capped Chickadee #2210-13348.  Originally banded as an HY bird on July 11, 2000, he is now more than five years old ("he" was recaptured in July of 2003 in breeding condition).  In his time here at Powdermill, we can only be confident of his stay as a resident breeder during the summer of 2003, because 35 of his past 39 recaptures have been between the months of October and March.

• As mentioned last week, determining the age of birds by tail feather shape alone is generally not very reliable because of individual variation and the possibility of accidental loss and replacement (i.e., adventitious molt).  Adventitious molt of tail feathers is particularly frequent in the case of chickadees.  There was no denying, however, that the broad and rounded retrices on our five year old recapture were quintessentially adult!

• Similar to the '3' fat HY male banded last week (click here), this HY female Blackpoll Warbler was carrying more than 6 grams of fat when she was banded on Thursday, weighing in at 17.9g (the average mass for HY female BLPWs at Powdermill is 11.3g).  More common in the east during fall migration than spring, many breeding Blackpolls from across the northern boreal forests make a trans-oceanic migration over the Atlantic to northern South America this time of year, an energy-demanding non-stop flight requiring BLPWs to double or nearly double their lean body mass with accumulated fat.  The heaviest BLPW recorded in our Relationships among body mass, fat, wing length, age, and sex for 170 species of birds banded at Powdermill Nature Reserve (2004. EBBA Monograph No. 1) is 23.2g!

• For this highlights page we've added another photo of the HY male Pine Warbler banded last week as a comparison to the similarly plumaged Blackpoll Warbler, with which it can be confused.  These two medium-sized greenish warblers have bold white wing bars in the fall, but the streaked back plumage of the Blackpoll Warbler (and of the similar Bay-breasted Warbler) helps to distinguish it from the plain-backed Pine Warbler.  Note, also, the brighter white edgings on the tertials and other flight feathers of the BLPW.

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• While not a new species for the season, the picture below was our first adult (AHY) White-crowned Sparrow  banded this fall, on October 15.

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• Unlike Purple Finches, HY male HOFI's acquire their reddish color in their first fall (after their first prebasic molt), so a HOFI like the one pictured below (banded on Sunday, October 16) can be confidently sexed female.  That it has completed its first prebasic molt is evidenced by a clear molt limit within alula feather group (the stack of three feathers just below the bend of the wing).  The largest of the three alula feathers (A3), not included in its incomplete first prebasic molt, differs markedly from the molted dark gray middle and upper alula feathers (A2 and A1, the latter sometimes called the alula covert) proximal to it.

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• A Fox Sparrow banded on Wednesday was our second new species for the week and brought the season species total to 102 (as of October 16).

• Despite a few efforts thus far, we are still looking forward to adding our first Northern Saw-whet Owl to the season totals.  So, may the coming October nights be moonless and calm!

Last Updated on 10/20/05
By Adrienne J. Leppold