North American Crane Working Group


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Horwich, Robert H. Developing a migratory whooping crane flock. 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. 85-95.


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


Research on crane reintroductions within the last 15 years has produced information necessary to effect a successful reintroduction of a migratory whooping crane (Grus americana) flock. There are 4 main problems to solve for such a reintroduction: (1) inducing a high survival rate of the reintroduced cranes, (2) encouraging normal reproduction with conspecifics, (3) teaching the reintroduced cranes the migration route, and (4) inducing fear of humans in the reintroduced cranes. Use of an isolation-rearing method by the author, using puppets, sounds, and costumes, has led to a consistent, over 80%, survival rate for the reintroduced young cranes after 1 year and migration. Such reintroduced sandhill cranes (G. canadensis) have followed wild cranes on the migration route and returned to their release area. They have learned to fear humans from their wild counterparts and have bred normally, raising fledged young. Results of 5 groups of experiments are reviewed: (1) cross-fostering has failed due to sexual imprinting on the wrong species, (2) releases of sandhill cranes have been successful and the survival rate has increased markedly with the costume method of rearing, (3) releases using the costume/isolation-rearing method have enhanced other programs, (4) creation of a nonmigratory flock of whooping cranes has met with some success but proper use of the costume method would enhance survival rates, and finally, (5) motorized vehicles have been used to teach young sandhill cranes a selected migration route. Recommendations for creating a migratory whooping crane flock include: (1) using as gentle a release as possible, (2) using young post -fledged chicks as the best candidates, (3) using developmental periods for enhancing releases, (4) using costumes to control the released chicks' behavior, (5) using costumes to enhance conspeci:fic breeding, (6) considering habitat site imprinting, (7) avoiding human contact and consequent imprinting, (8) using the parent model and isolation-rearing for enhancing following of ultralight aircraft by the chicks, and (9) considering cost effectiveness in the reintroduction process. Procedures for effecting a successful reintroduction are elaborated.