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Thursday, December 26, 2013

Saw-whet Banding Season Summary

The North Branch Nature Center completed its first season of Northern Saw-whet Owl banding this fall with a total of 54 owls captured between two banding stations. At NBNC’s property in Montpelier, 21 owls were banded in six nights (~21 hrs) and at Shelburne Bay, 33 owls were captured in 22 nights (~75 hrs). An additional two recaptures occurred at Shelburne Bay of owls that had been banded there a few days before.

Recaptures between

Much to our excitement, this season we had three foreign recaptures (owls that had already been banded at other banding stations).  One owl captured October 24, had been banded in Montreal, Canada just 16 days earlier.  And two other owls, captured October 24 and November 4, had been banded last fall near Allentown, PA (within 15 miles of each other).  With each recapture, will help reveal how Saw-whets utilize Vermont during their journey south.

While this was only our pilot year of owl banding, we can still learn a lot from the owls we caught.  At our Shelburne Bay site, only around 12% of our captures were of hatch-year birds (those born this past spring and summer).  This low proportion of young individuals typically occurs in years of food shortage on the breeding grounds, during which few young owls are born.  Other Saw-whet banding stations in the east experienced a similar lack of hatch-year birds this fall, along with low numbers of migrants overall.  

At the NBNC station, however, hatch-year birds accounted for a much higher percentage of captures at 38%.  It is possible that owls migrating through NBNC come from a different population than those migrating through Shelburne Bay, accounting for a difference in natal productivity and hence the differing proportion of hatch-year birds.  This is hard to confirm, but it is interesting to think about how the geography of Vermont’s landscape may funnel owls from different populations through different migratory corridors.  

In keeping with NBNC’s devotion to education and outreach, over 200 kids and adults visited the banding stations in Shelburne and Montpelier to observe science in action.  It is our hope that this unique opportunity both deepens participants’ interest in nature and empowers them to do something positive for the environment.  Thanks to everyone who visited the banding stations this fall, and special thanks to volunteers Mattias Sirch, Abby Sirch, Rebecca Gray, and Aileen Lennon. 
Photo by Brian Jenkins, 3rd Stone Images

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