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March 17, 2014

Whooping Crane Update

Wade Harrell, U.S. Whooping Crane Recovery Coordinator

Winter 2013-2014 Whooping Crane Survey Results 
304 Wild Whooping Cranes Estimated

The U.S. Fish and Wildlife Service (Service) has estimated the number of whooping cranes in the Aransas-Wood Buffalo population present in the primary survey area centered on Aransas National Wildlife Refuge. Preliminary analyses of the data indicated 304 whooping cranes (95% CI = 260–354; CV = 0.08) inhabited the primary survey area (see map). This estimate includes 39 juveniles (95% CI = 32–47; CV = 0.10) and 116 adult pairs (95% CI = 100–135; CV = 0.08). Recruitment of juveniles into the winter flock was 15 chicks (95% CI = 13–17; CV = 0.07) per 100 adults. The precision of this year’s estimates was improved and achieved the target set in the protocol (i.e., CV < 0.10). Improved precision is due to increased observer experience and refinement of methods.

During winter 2012–2013, 257 whooping cranes (95% CI = 178–362; CV = 0.19) were estimated in the primary survey area and during winter 2011–2012, 254 whooping cranes (95% CI = 198–324; CV = 0.13) were estimated. Examination of the 60-year trend in whooping crane numbers shows an increase with occasional, periodic declines. A continued upward trend in whooping crane numbers over the last three years was observed, and is consistent with the long-term growth trend.
 

SurveyArea_520
 

During winter 2013–2014, the primary survey area (approximately 154,000 acres) was surveyed seven times between 11 December and 23 December 2013. During the same period, the secondary survey area (approximately 101,500 acres) was surveyed twice to monitor ongoing expansion of the whooping crane’s winter range.

The data and results presented in this report are preliminary and subject to revision. This information is distributed solely for the purpose of providing the most recent information from aerial surveys. This information does not represent and should not be construed to represent any U.S. Fish and Wildlife Service determination or policy. 

Last Updated: Mar 24, 2014
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