• December marks the end of fall migration and the beginning of the official winter banding season here at Powdermill.  The local bird population largely shifts to winter resident, most of which are previously banded birds.  As a result, our recapture numbers at this season usually far outnumber our "new" birds.  In general, our banding effort is greatly reduced in winter compared to our migration banding effort, both in terms of number of days of operation and number of net and trap hours per day.   During the current period, we banded on just eleven out of a possible 22 days, catching 120 new birds and processing 159 recaptures.  We want to thank Randi Gerrish and Felicity Newell for their help with the banding.

• Of note this month was an adult male Common Grackle banded on December 15, 2004.  This is only the fifth time in 43 years that we have banded a COGR in December (three others have been captured in January).  Also noteworthy, we added four more Fox Sparrows to our year's total in early December (the last on Dec. 5).  Fox Sparrows are rare winter residents at Powdermill, and the four banded most likely represented late migrants at the tail end of a very good fall migration.  Interestingly, however, two unbanded FOSPs were seen at Powdermill during the 30th annual Rector CBC on December 18.

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• Despite somewhat lower than usual participation, this year's Rector CBC was very productive.  At just over 5,000, the total number of birds seen was about average for recent years, but we set a new record for number of species seen on count day with 70.  The previous high species count was 64 in 1997.  Several species were observed in record high numbers and many made just their second or third appearances ever on the Rector CBC.  For more details on the count and a full table of all birds and totals for individual species, click here.

• We were forced to trade a week of routine early December passerine banding at Powdermill for a week of owl banding near Duluth, Minnesota.  Mike Lanzone, Assistant Project Coordinator for the 2nd PA Breeding Bird Atlas and Field Ornithologist at the Powdermill Avian Research Center, and I traveled there on Monday, December 6  in order to take advantage of the phenomenal (maybe even unprecedented) northern owl invasion reported this early winter in parts of the upper midwest.  In the photos below, Mike and I pose with two of ten Great Gray Owls that we and Mike's friend and colleague, Frank Nicoletti, banded in one day, which actually set a new U.S. single day banding record for the species!

• As we have mentioned before, Mike and Powdermill's Field Ornithology Projects Coordinator, Bob Mulvihill, are working on a photographic guide book series to ageing and sexing North American birds in the hand.  It will be published in six volumes by Princeton University Press.  The second volume (co-authored with Jerry Ligouri) will cover diurnal raptors and owls.  This winter's owl invasion in Minnesota provided an unparalleled opportunity to obtain photographs and data needed for completing accounts for Great Gray Owls, Northern Hawk Owls, and perhaps other northern species as well.

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In the photo below (left) Mike photographs the spread wing of one of 20 Northern Hawk Owls caught during the week; the photo on the right shows the extensively worn unmolted head and back feathers of an adult female Great Gray Owl, which made her appear almost snowy white at a distance.

• The owl invasion this winter certainly has been a hot topic among birders across the nation.  Unlike the high numbers of Northern Saw-whet Owls (see our past pictorial highlights for November 2004), an invasion of these other northern owls was not unexpected.  Great Gray Owl populations, for example, regularly cycle with the crash of the vole populations in Alaska and Canada, resulting in the birds' expansion south in search of food, and this was predicted to be a movement year.  The record numbers, however, were not anticipated: 700 Great Gray Owls and 500 Northern Hawk Owls have been estimated from northern Minnesota alone!

• As leading owl biologist and author of "Owls of the World," Dr. James Duncan, recently wrote on the Wisconsin Birding Network, a dramatic crash of vole populations in the North resulted in virtually no reproduction by Great Gray Owls this summer and extended shortages of food through the fall forced the birds even farther south and in larger numbers than usual during such periodic irruptions.  Recall that a similar scenario was believed to be at the root of the unexpectedly heavy NSWO migration this fall.  As with the NSWOs, banders in MN (including us) have been catching few or no hatching year birds.  Of 18 Great Gray Owls (left photo below) that we banded, only one was a hatching year bird, while eight of 20 Northern Hawk Owls (right photo below) were hatching year birds.

• While photographing and studying the molts of owls were our main objectives, we hoped to also catch a few other norther species to fill in some gaps for the photographic guide.  We successfully caught this one Northern Shrike, a hatching year bird of unknown sex.

• We cannot give enough thanks to Frank Nicoletti (at left in the photo below), raptor biologist of Hawk Ridge Bird Observatory, a leading expert in raptor molt, and advisor and friend of Mike Lanzone (at right in the photo below) from Mike's earliest days in this field--without Frank's help and hospitality, we certainly would not have had such great success on this banding adventure.

 

• After such a productive week in Minnesota, Mike decided to return to MN over the holidays, this time with his family.  So, we are certainly looking forward to having more highlights to share in the new year from the second owl banding expedition up north.

• Finally...

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Last Updated on 12/23/04
By Adrienne J. Leppold