Trumpeter Watch – Ten Years of Christmas Bird Count Data

Trumpeter Swan Landing by John VanOrman
Trumpeter Swan Landing, photo by John VanOrman

Summer is here and we at The Trumpeter Swan Society working on Trumpeter Watch are reviewing data from our first winter season. We are looking at several sources of data, generated by Citizen Science, to better understand the pattern of winter use for expanding populations of Trumpeter Swans. If you took part in this past winter’s 110th Annual National Audubon Society’s Christmas Bird Count, you may have contributed. A summary of the data provides us in essence a snapshot of early winter distribution across states we are tracking south and adjacent to the 40th parallel. Archives of the Counts are readily available and their census over repeated years allows us took look at a relative measure.

Here is the snaphot we found. Oklahoma, Kansas and Missouri had Trumpeter Swans in more than one Count circle for five or more of the last ten years. Surprisingly, eastern Colorado has as well. In 2003, a total of 10 Trumpeters were counted across the 18 states we tallied, found in 4 of the states. A surge of Trumpeters in Oklahoma brought the total to 40 one year later (28, found in 4 Count circles). From 2005 to 2007 that number actually varied and declined, and that total was only passed again in 2008, when 59 individuals were tallied over 5 states. Fifty-one of these Trumpeter sightings occurred in Missouri, mainly at Squaw Creek National Wildlife Refuge that year. In 2009 wintering numbers took a giant leap, with a total of 403 tallied in the region. Missouri was the stronghold, recording 374 individuals in 8 Count circles, 337 Trumpeters in the Confluence Circle alone(Riverlands Environmental Demonstration Area)! Kansas had numbers in the double digits for 2009 and 2010 as well (16 each year) quite a bit shy of the 600 recorded for Missouri in 2010.

At the start of this new decade there were more Trumpeter Swans wintering south of the 40th parallel than in states immediately north of (Nebraska), or having that line of latitude cross through (Ohio, Illinois, Indiana, Pennsylvania) combined with two states with restoration flocks we are tracking (Iowa and New York). All states should be on the alert. Florida, Kentucky and Texas have all had 1 count in the last decade with a recorded Trumpeter. New Mexico, Mississippi, and Virginia claim 2 Counts each in that period. Arkansas first recorded Trumpeters on a Count circle in 2007, a year ahead of their restoration release programs began. Still waiting for a first CBC record Trumpeter Swan are Alabama, Delaware, Louisiana, New Jersey, Tennessee, and West Virginia. Who knows what 2011 may bring!

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