North American Crane Working Group

 

Date of this Version

2001

Document Type

Article

Citation

Cannon, John R., Johns, Brian W., and Stehn, Thomas V. Egg collection and recruitment of young of the year in the Aransas/ Wood Buffalo population of whooping cranes. In: Ellis, David H., ed., Proceedings of the Eighth North American Crane Workshop, 11–14 January 2000, Albuquerque, New Mexico (Seattle, Wash: North American Crane Working Group, 2001), pp. 11-16.

Comments

Reproduced by permission of the North American Crane Working Group (NACWG).

Abstract

We present data for 61 years (1938 to 1998) on the recruitment of juvenile (i.e., young-of-the-year) whooping cranes (Grus americana) for the 1 natural wild population that nests in the vicinity of Wood Buffalo National Park (WBNP) in Canada and migrates annually to wintering grounds in the vicinity of Aransas National Wildlife Refuge (ANWR) on the Gulf coast of Texas in the United States. We divide these years into 2 data sets: years during which 1 of 2 eggs was collected from WBNP nests (to develop captive populations and to conduct reintroduction experiments), and years during which no eggs were collected. We compare these 2 sets of years in terms of recruitment of juveniles into the AransasIWood Buffalo Population (A WP) and fall arrivals at ANWR of "twin" juvenile birds with one set of parents. Recruitment of juvenile birds into the A WP (defined as the percent of juvenile cranes in the A WP arriving at ANWR in the fall) was significantly (P = 0.032) greater during years of no egg collection at the nesting grounds. During the 34 years of no egg collection at WBNP, 16 pairs of "twin" juveniles arrived at ANWR in the fall. During the 27 years of egg collection at the nesting grounds, no pairs of "twin" juveniles arrived at ANWR in the fall.