• Weather continued to impact our banding this week with temperatures reaching well into the 80's all six days.  Numbers were a bit disappointing with only 254 birds banded, making it the lowest weekly total since the second week of April.  Species diversity also dropped this week by four, despite the addition of eight new species to our season list, five of which were warblers.  With 25 banded, Magnolia Warbler took over the number one spot this week.

As always, we thank our faithful volunteers Randi Gerrish, Carroll Labarthe, Annie Lindsay, and Felicity Newell, for their help this week with banding.

• Tuesday, May 11:  We banded 26 species of birds making it the most diverse day of the week, and

also a very exciting one considering that our one new species added to the spring 2004 season list has only been captured one other spring since 1998 and in only 18 spring seasons in the 43 year history of the banding program.  It was a second year (SY) female Yellow-throated Warbler.  Males and females of this species are similar, but females have comparatively less extensive black on the forecrown and a hint of buffy coloration on their flanks.   There are three recognized subspecies in North America.  The more westerly distributed white-lored subspecies, Dendroica dominica albilora, is the form most frequently encountered at Powdermill.  It is distinguished by a white rather than yellow supraloral stripe (above the eye), and its upper chin usually shows white also.  Although the individual banded at Powdermill appeared to have a very long bill, albilora actually has a shorter bill, on average, compared to the other YTWA subspecies.

• Wednesday, May 12:  While no new species were banded today, this pair of Scarlet Tanager males provided us a good photo opportunity for contrasting the age classes.  The top photo, an unquestionable adult (ASY) male and the bottom of an immature (SY) male - all alula, primary coverts, and flight feathers being retained juvenal.

 

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• Thursday, May 13:  Three new species were banded today, including both Yellow-billed and Black-billed Cuckoos, providing us with some good demonstration birds for our visiting school group from St. Edmunds Academy in Pittsburgh.  Just how many people can we fit in the banding lab?!  Shortly after this photo was taken we moved the demonstration outdoors, so everyone could stretch their wings a little.

• The pictures below are of two of the cuckoos banded today.  The above photographs are of the Black-billed Cuckoo head and tail followed by photos of the Yellow-billed Cuckoo head and tail.  The bright red fleshy eye ring in the Black-billed is denoted in most field guides as an ageing characterisitc, indicative of an adult (immatures having a yellow eye ring).  This is, in fact, only a reliable ageing criteria in the fall, as over winter, immature's yellow eye ring turns red, resembling that of an adult (we banded both cuckoos simply as, after hatching year, or AHY).  Undertail patterns are also distinctive between species and can be helpful marks for identifying birds in the field.  Note the Black-billed Cuckoo's tail from underneath is gray with small white tips while the Yellow-billed Cuckoo's tail is more blackish with large white spots.

• Cuckoos are birds well known for brood parasitism, mostly because of their European counterpart.

   - Females that lay their own eggs in other species nests or other birds nests of the same species
    are known as brood parasites, basically, pawning off any parental duties of rearing their own young -
European Cuckoos are notorious brood parasites and lay their eggs only in the nests of other species of birds.  The host parent may abandon the nest or incubate the eggs as its own.  Once hatched, the cuckoo, blind and featherless, will push all other contents of the nest out over the edge, leaving the parents to devote all their care to the young cuckoo.  Our North American Cuckoos, actually rarely brood parasitize other species of birds and only occassionally brood parasitize within their own species or opposite cuckoo species.  Of course, the most famous North American brood parasite is the Brown-headed Cowbird.

• Friday, May 14:  We added Blackpoll Warbler to our new species list (see photos below for Sunday, May 16 when we banded 8 of them) and also netted this immature (SY) male American Redstart, which well represents the difference between young males and females of this species.  SY males do not obtain their black and orange plumage until their second prebasic (second fall) molt; until then, they can very closely resemble females.  What usually separates young males from females is a variable amount of black flecking on the face and throat, as seen in the photo below.

• Empidonax flycatchers are notorious for being confusing to identify both in the field and in the hand.  Below are two photos of an adult (ASY) Acadian Flycatcher of unknown sex banded today.  Unlike in the field, banders do not have the benefit of using calls or songs to identify species (they cannot, for example, reliably distinguish between Alder and Willow flycatchers, typically banding these species under the old name of "Traill's Flycatcher," which is how they were known before they were taxonomically "split").   So, how then did we determine this bird was an Acadian Flycatcher?

• While banders do not have the benefit of using songs and calls for identifying Empids, we are able to use various measurements and physical characteristics, such as wing feather shape (i.e., in this case, an unemarginated primary number six) and leg (i.e., in this case, grayish, rather than blackish) and mouth lining color, not readily seen in the field.  The simple act of this bird opening its mouth would have confirmed, had we any doubt, that this was, in fact, an Acadian Flycatcher.  Acadians are the only Empids that have this pale pink, to occasionally pale yellowish, mouth lining color seen in the photo below.  All other Empids are typically bright orange or yellow.  We have noticed that immature ACFLs (even SYs in spring) tend to have yellower mouth lining than adults.

• Saturday, May 15:  We banded two more Cedar Waxwings today, the first of which for the season were captured on Thursday of this week.  The photo below is of an immature (SY) male.  Immatures can rarely show hints of small wax tips on a few secondary flight feathers.  Even more noteworthy on this bird, however, are the two different colors in the tail band.  Following along with our American Redstart discussion from last week concerning the influence of carotenoids in feather coloration, this waxwing's orange tail feathers grew in as a nestling when it was being fed primarily a diet of Tartarian Honeysuckle berries, a food rich in a red carotenoid pigment called rhodoxanthin.  This red pigment is structurally similar to the yellow carotenoid pigments normally deposited in the tail tips of CEDWs, and birds that consume a lot of it while growing their feathers can develop abnormally orange to red tail band color.  This bird subsequently lost a few of its tail feathers and grew them in at a time when it was no longer feeding on (or, in this case, being fed) fruits containing red rhodoxanthin.  In the absence of this unusual red carotenoid pigment in its diet, the CEDW grew replacement feathers having normal yellow coloration.  Studies of this phenomenon at Powdermill are summarized in the publication "Evidence supporting a dietary basis for orange-tipped rectrices in the Cedar Waxwing," by Mulvihill et al. (1992. J. Field Ornithol. 63:212-216).

 
 

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• Sunday, May 16:  We banded our first Blackpoll Warbler on Friday, May 14 but felt it appropriate to highlight them here as we had the highest daily banding total for this species of any spring season in the past 43 years.  Eight new birds were banded, and actually, only eleven other days in Powdermill's history have Blackpoll daily totals exceeded or matched this total (all during fall migration).  The photo below is an adult (ASY) male.

• Two new species were also added to the season banding list, Black-throated Green Warbler and this immature (SY) Golden-winged Warbler.  It's been more than ten years since we have banded this species in double digits in the spring, so it was quite a delight to see him in our nets.  Powdermill's banding data has shown continual decline in numbers of GWWA over recent years, due to local changes in habitat.  GWWA are well known habitat specialists and, in earlier years, Powdermill was dominated by the early successional old field habitats near woodland edges favored by GWWA.   Despite some ongoing habitat management in the immediate vicinity of our net lanes, Powdermill has steadily become more wooded and its old fields have advanced to later successional stages less suitable for GWWAs and some other species, like Field Sparrow and Yellow-breasted Chat, which also show steady declines in banding totals here.

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• Due to the overwhelming number of incredible photo ops. this week, we have added some links below for  more great pictures of birds banded this week at Powdermill Nature Reserve. Note:  You will have to use your browser back button to return to this page from the links below.

• Spotted Sandpiper (AHY/U)
• Black-throated Green Warbler (SY/F)
• Mourning Warbler (SY/M)
• Wilson's Warbler (SY/M)
• Canada Warbler (ASY/M)
• Indigo Bunting (SY - male/female pair)

Last Updated on 5/19/04
By Adrienne J. Leppold