Pictorial Highlights_ 09291005

POWDERMILL NATURE RESERVE
BANDING NOTES AND PICTORIAL HIGHLIGHTS
September 29-October 5, 2003

September 29-October 5, 2003: Over the course of the week, the weather turned truly autumn-like for the first time. Randi Gerrish and Carroll Labarthe helped with the banding on Wednesday and Friday, respectively. We had our first killing frost on Friday morning, 10/3, and the leaves at Powdermill are only just now beginnning to turn colors to any degree (perhaps 2-3 weeks later than usual). Another cold front swept through on Friday night, bringing with it cold rain that paused just long enough for us to sneak in a couple hours of banding early on Saturday morning. Shortly after closing the nets due to the return of rain later on Saturday morning, we banded a bird that we didn't catch. The mystery (mist story?) goes like this...

It was a dark and stormy Saturday morning. We were sitting in the office after a couple hours of banding when we got a phone call from a gentleman who said he had found some kind of bird with webbed feet, maybe a "small loon," stuck in the middle of a rain-slicked parking lot in a shopping plaza at the southern edge of Latrobe, a small town about 10 miles northwest of Powdermill. The man, Tom Burns, had kept the bird in a box in his garage overnight, took the bird with him to work at McInchok Sanitation in Waterford (about 7 miles from Powdermill), and called us about it first thing Saturday morning.

Along with our visiting British bird banding colleague, Professor David Norman, we arranged to meet Tom at the Sheetz store parking lot in Oak Grove (between Waterford and Powdermill) to take a look at his bird, and, if necessary, to transport it to a local wildlife rehabilitator. The "small loon" turned out to be an immature Pied-billed Grebe, and a quick inspection showed that it was in surprisingly good condition, with only a small chip on its upper bill to show for its crash landing!

Tom Burns, from McInchok Sanitation, about to hand
the small Pied-billed Grebe he rescued over to
Powdermill banders Bob Mulvihill and Mike Lanzone

We returned to Powdermill, where we banded, measured, weighed, and immediately relased the grebe onto our own Crisp Pond. Thanks to Tom's quick and thoughtful intervention, the lucky grebe was spared a very wet and stressful night stuck in the middle of a cold, hard parking "pond," and it actually still had a hefty fat deposit by the time Tom brought it to us. In fact, at nearly 419 grams (not quite a pound), it was the second heaviest PBGR we have ever banded!

Most of the PBGRs we have banded here (this it just our seventh in 42 years) have been stranded, but otherwise uninjured, birds like this one, found in the vicinity of Powdermill. Grebes (as can be seen in the photo below of Prof. Norman holding the rescued bird after banding) have their lobed feet set very far back on their body. They serve very well for propelling them underwater, where they swim after aquatic insect and small fish prey, but are very poor for locomotion on land. In fact, grebes and loons can do little more than stand on land! In addition, grebes (and also loons) have very small narrow wings for their size (larger wings actually would be a hindrance to them while swimming underwater), and so require a fairly long "runway" (make that paddle-way!) to get up enough speed to generate the lift needed for becoming airborne. Simply put, a grebe cannot take off from dry land (or even from a rain-slicked parking lot!). They must flap while paddling vigorously across the water surface of a pond or lake of sufficient size in order to take flight. We know that Crisp Pond at Powdermill is big enough for a PBGR to fly off from, because PBGRs appear (and disappear) fairly commonly on our pond during migration.

Dr. Norman holding the lucky Pied-billed Grebe rescued by Tom Burns

Prof. Norman gently releasing the grebe onto Crisp Pond

Instead of ducking (O.K., grebe-ing) underwater as soon as it was released, Tom Burns' little grebe, now wearing band #676-18195, paddled a couple feet from shore and, with all eyes on it, drank thirstily, ruffled (or unruffled, as the case may be!) its feathers a bit, and promptly went to sleep! By afternoon, it was swimming around Crisp Pond like it owned the place, and by Sunday afternoon it apparently had continued on its migration odyssey, having learned a thing or two, we hope, about the odd-seas called parking lots!

Our busiest day of the week was Thursday, 10/2, when we banded 165 birds of 40 species and processed an additional 20 recaptures. Magnolia Warbler (20 banded), Gray Catbird (19), and Swainson's Thrush (18), and Common Yellowthroat (14) were the most common species in our nets on this day, but it was one of the ten Scarlet Tanagers that we caught that made the day especially noteworthy. The bird, pictured below, looked and sounded unusual for a SCTA. Click here for some extra web pages where you can see and hear more about it.

On October 1, we had a variety of vireos (five species, including a White-eyed Vireo retrap) and a round-up of wrens (four species, including a Carolina Wren retrap). With a very slight amount of photo editing, we managed to get some pretty well-posed shots of three species from each group, all caught together in the same net round, and all photographed together (really!)

First, the vireo trio...from top to bottom (and, also, from most prominent face pattern to least): Red-eyed (a brown-eyed HY bird), Philadelphia (an especially dull-colored individual; i.e, not as yellow as most on the throat and breast), and our very first Warbling Vireo of the season.

Next, the wren row (from left to right: Marsh, House, and Winter Wren; below these, the Carolina Wren reptrap caught later in the day)

We banded our first Orange-crowned Warbler, a hatching year male, on Tuesday, 9/30. It had a fat score of 1 (on a scale of 0-3), and weighed 8.8 grams. He was recaptured again on 10/1 and 10/4, ranking a fat score of 2 and having gained 0.8 g by its last handling).

Six Common Yellowthroats were banded on 9/30--half were adult (after hatching year, or AHY) males, which, even in their fall plumage, ordinarily have large, extensively black face masks like the feisty bird pictured below.

The ability of migrants like the OCWA and COYE to find enough resources at a stopover site to deposit fat sufficient to fuel at least one whole night's migration or, at a minimum, to enable them to continue moving on in search of a better stopover area or habitat for migratory fattening, is critical to their survival and to the successful completion of their long migrations to and from the Neotropics. The identification of important stopover areas and preferred habitats for migrant songbirds in Pennsylvania currently is being investigated using a combination of radar data, GIS data, and acoustical monitoring of nocturnal flight calls.

The project, entitled "Oases Along the Flyway," is the conception of Dr. David Mizrahi, Vice-president for Research at New Jersey Audubon, working out of Cape May Bird Observatory. Dr. Mizrahi has obtained some very interesting and conservationally very important results using this approach to study migration of birds through central New Jersey, and he recently has expanded his project to include a much broader area of the mid-Atlantic region. We are pleased at Powdermill to be a partner in this study, providing David with a site for the installation of one of his nocturnal flight call recording microphones, and also providing him with access to our banding data as a means for "ground-truthing" his radar and microphone data.

In addition to this, banding data also can provide a very important category of evidence for assessing and/or confirming the quality of particular areas and habitats as stopover sites. By recording a measure of the visible fat of migrants caught for banding, and by documenting changes in visible fat deposits and body mass through subsequent recaptures, site and/or habitat quality can be assessed directly.

At Powdermill, many of the birds we band have large fat loads initially and/or accumulate large fat deposits during the course of their stopovers here (typically lasting from a few days to a week or more). Below is a picture of a migrant Magnolia Warbler banded at Powdermill this week that had amassed very large fat reserves (the bird's feathers have been wetted slightly to allow them to be pushed aside for the photo). The mounded yellowish mass at the left center of the photo is the large furcular or interclavicular fat deposit (i.e., in the space between the fused clavicles, or collar bones, called the furculum or "wishbone" in birds); the yellowish band at the right center of the photo shows just the upper edge of a very large abdominal fat deposit. In between the two fat deposits can be seen the large reddish pectoral musculature (the so-called flight muscles), which are attached to the bird's keel, or sternum.

A maximally fattened MAWA like this HY female may weigh 12 grams or more, nearly double its lean body mass. The caloric density of this amount of fat is more than sufficient to supply the energy demand of a small bird like this bird making a non-stop nocturnal migratory flight of 400 miles or more--and this is just one of several such flights needed to take it all the way from its Canadian nesting grounds to its Central American wintering grounds! And to think, this MAWA is just one of hundreds of thousands of small songbirds making these journeys, traveling across vast stretches of sky by night, sheltering in forests and fields by day, over and around each and every one of us at this time of the year.

By unraveling some of the phenomenon's many mysteries, the active study of bird migration by field ornithologists and bird watchers around the world, using tools such as banding, radar, flight call recording, feather isotope analysis, biometrics, direct observation, and much more, just seems to make the whole spectacle that much more fascinating! One thing's for certain--knowing more about this critically important component in the annual cycle of so many species of birds prepares us to do more and, importantly, to do better, in the name of their conservation.

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