Aransas Wood Buffalo Population Update

Update on the Aransas Wood Buffalo Population of Whooping Cranes

The Unison Call – Vol. 27 No. 1

Breeding pair surveys in May detected 78 nests (an additional nest was inferred based on observation of a pair with offspring during August surveys), 15 of which were outside the area designated as critical habitat and seven of which were outside Wood Buffalo National Park; 18 pairs without nests were also observed. Surveys in August detected 45 juveniles; 43 pairs had one juvenile each and one pair had two juveniles. Annual productivity was 0.57 juveniles per nest, well above than the 20-year average of 0.48 but within the long-term natural range of variation.

The above are preliminary results from the Canadian Wildlife Service, contributed by Mark Bidwell.

Summary of Aransas Wood Buffalo Population Breeding Surveys for 2013-2016

Aransas Wood Buffalo
†Most nests ever recorded. *All family groups had a single offspring; **two families with twins; ***one family with twins; #20-year average is 0.48 chicks per nest. Wood Buffalo National Park (WBNP) 2013 data are from Harrell and Bidwell
(Oct. 2014), Report on Whooping Crane Recovery Activities; WBNP 2014 data are from Northern Journal (, Sept. 1, 2014, quoting Mark Bidwell; WBNP 2015 data are from Bidwell and Conkin (March 2016), Recovery and Ecology of Whooping Cranes: Monitoring of the Aransas-Wood Buffalo Population during the Breeding Season 2015 Report. WBNP 2016 data are preliminary results from the Canadian Wildlife Service, with thanks to Mark Bidwell.

Aransas NWR winter counts are from ‘Whooping Crane Updates’ at the ANWR website. ‡Estimated numbers of birds outside the primary survey area in 2013, 2014, and 2015 were 6, 6, and 9, respectively. (95% CI means 95% confidence interval) — Ed.

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