Powdermill Nature Reserve
Spring 2003 Banding Summary

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The bird-banding programat Powdermill Nature Reserve, a 2,000 acre field biological station of Carnegie Museum of Natural History located in the Laurel Highlands region of southwestern Pennsylvania, was in operation on 74 out of a possible 93 days during the spring 2003 season (March 1 through June 1).  A nearly average 2,479 birds of 105 species was banded, with the busiest day being 145 birds of 38 species on May 15--this was the daily maximum for both number of birds and number of species during spring 2003 (Figure 1).   Although not as busy a season as last spring (when 3,475 birds of 109 species were banded), this one day total for number of birds and number of species banded exceeded the highest daily totals recorded last spring (137 birds banded on 4/27/02 and 37 species banded on 5/15/02).   The catch on this spring's busiest day was dominated by wood warblers (16 species), including 27 Magnolia Warblers, 12 Common Yellowthroats, nine American Redstarts, and seven each of Chestnut-sided and Black-throated Blue Warblers.
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Figure 1.  Daily banding totals and species counts for spring 2003 at Powdermill Nature Reserve.  Smaller inset graph shows the relationship between daily banding totals and daily species counts.

The timing of spring migrationacross species is what produces the pattern of daily banding totals (both in terms of number birds and number of species) like that shown in Figure 1 above.   Figure 2 below is based on the cumulative spring banding totals for more than 75 species over the last 40 years at Powdermill.  It shows interspecific differences in seasonal occurrence (ranging from the entire spring season, i.e., March 1 through May 31, e.g., for American Robin and American Goldfinch, to little more than two weeks in mid- to late May, e.g.,  for Bay-breasted and Blackpoll warblers), as well as patterns of seasonal abundance for each species (and for the sexes within selected species).  Because the abundance scale for each species is different (and not shown), however, seasonal abundance among species cannot be compared directly.
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The graphs making up Figure 2 depict changes in relative abundance for species across the spring season.  In species for which all or most birds can be sexed, the timing of migration of the sexes is shown separately (males in blue; females in red); species with some or all birds of unknown sex are shown in pale yellow.  In all species, the area of the curves (including for the sexes when they are distinguished) is proportional to abundance for any given banding date.  For example, in Ruby-crowned Kinglet, the first three weeks of the species' migration at Powdermill is entirely comprised of male birds, followed by a week or more when the sexes occur in about equal numbers, and finally by a two week period when virtually all of the RCKIs banded are females.  From Figure 2, is is apparent that, overall, the species is most abundant at Powdermill during the roughly ten-day period in late April when the sexes co-occur in migration.

Figure 2 shows that the early part of the spring migration at the Powdermill banding station (i.e., March through early April) is dominated by captures of winter resident individuals of species like Blue Jay and Black-capped Chickadee and of no more than a dozen or so early migrants, like Golden-crowned Kinglet, Fox and Song sparrows, and Dark-eyed Junco.  The middle portion of the spring season (i.e., the last 2-3 weeks of April) brings the bulk of Ruby-crowned Kinglets and other sparrows, blackbirds, and finches (e.g., Chipping, Field, White-throated, and Swamp sparrows, Brown-headed Cowbird, and Purple Finch), while the height of the migration in mid-May (i.e., 10-20 May; see also Figure 1) coincides with flights of the greatest diversity of migrants, especially Neotropical migrants like Ruby-throated Hummingbirds, vireos, thrushes, orioles, and most wood warblers.  The tail end of the migration (i.e, late May) is dominated by several species of flycatchers and later migrating species of thrushes and wood warblers.  The end of May cutoff for the graphs in Figure 2 clearly cuts off the migration artificially for several of these species, some of which are still migrating through Powdermill as late as mid-June.
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Figure 2.  Timing of spring migration of selected bird species at Powdermill Nature Reserve, based on cumulative daily banding totals from March through May, 1962-2002.

The real highlight of the spring 2003 banding season wasn't a bird but an event, the 80th annual meeting of the Eastern Bird Banding Association, held at Powdermill and nearby venues from 4-6 April.  This meeting, attended by nearly 100 people, was followed by a sanctioned North American Banding Council bander level certification workshop from 6-8 April.  Both events were a great success despite the fact that the prevailing weather on both occasions was mostly inclement!  A very special guest at the EBBA meeting was Dr. Lukas Jenni, Scientific Director of the Swiss Ornithological Institute and co-author of the extraordinary Moult and Ageing of European Passerines, who was the meeting's keynote speaker and who also gave a very informative and  interesting workshop on the European ringing (=banding) schemes and techniques.  Another special guest, British ringer, Dr. David Norman, contributed much of significance to both the workshops and the scientific paper sessions at the EBBA meeting, and he stayed on to provide invaluable assistance during the NABC certification session.   All of us here at Powdermill, and all those in attendance at these events, were signally fortunate in having the opportunity to "expand our worlds of banding" by meeting and learning from these extraordinarily knowledgeable gentlemen.  We can't thank them enough for their participation--they truly made these events a once-in-a-lifetime experience for all of us!