National Elk Refuge Trumpeter Swan Survey Results
For Immediate Release
October 17, 2014
The National Elk Refuge completed a summary of the 2014 trumpeter swan nesting season this week, bringing with it good news regarding nesting pairs on the refuge. The survey supports efforts by the Greater Yellowstone Trumpeter Swan Working Group and monitoring goals identified in the National Elk Refuge’s draft Comprehensive Conservation Plan.
Biologist Eric Cole and volunteers Betty and Chuck Mulcahy made weekly outings from mid-May through the end of September to assess trumpeter swan numbers and activity at six sites on the refuge. In addition to documenting the maximum number of adult birds and nesting pairs, they noted the number of successful nests. They also recorded the number of cygnets that hatched and subsequently fledged.
The research included more than just bird numbers; the timing of the events was also key in the documentation. Cole’s summary includes when the nests were initiated, when cygnets hatched, and during which weeks any loss of cygnets was observed. When possible, the researchers noted the cause of both nest failures and swan mortality.
The summary published this week documented four nesting pairs on the refuge, a record high that has only been duplicated six other times since 1938. Also, twelve cygnets hatched on the refuge in 2014, with ten surviving to fledge later in the season. Though no match to the 18 cygnets that hatched and fledged in 2007, the number exceeded the ten–year average of seven hatched cygnets and six that fledged.
The National Elk Refuge is an important contributor to an objective of 18 nesting pairs in the Wyoming Snake River core area, set by the Trumpeter Swan Management Plan.
Higher swan production is correlated with warm, dry spring conditions. This past season, precipitation was below average in both May and June.
Additional photos of trumpeter swans are included in the “Birds of the National Elk Refuge” photo set on the refuge’s gallery at http://bit.ly/1sueAOj.
– FWS –