Date of this Version
Littlefield, C.D. Sandhill crane migration chronology and behavior in northwestern Texas. In: Hartup, Barry K., ed., Proceedings of the Eleventh North American Crane Workshop, Sep 23-27, 2008, Wisconsin Dells, Wisconsin (Baraboo, WI: North American Crane Working Group, 2010), pp. 62-65.
Migrant lesser sandhill cranes (Grus canadensis canadensis) were monitored during 1990-2000 in northwestern Texas as flocks were arriving in autumn and departing in spring; cranes were counted as they passed over an observation point 23 km north of Sudan, Lamb County, Texas. Mean flock size was 34.5 (SD ± 32.6) in autumn and 58.2 (SD ± 45.0) in spring. Most autumn migrants (69.6%) passed in the afternoon, whereas in spring 94% migrated in the morning (1000-1200 hr). Peak period of autumn passage was in October (65%), and in spring all observations were in February-March with the peak usually in late February. For arriving cranes headwinds had little influence, but 84% departed when winds were from the southwest. Retro-migration was recorded during both migration seasons; autumn retro-migration events appeared to be associated with human disturbance south and southwest of the study site, but in February and March it was associated with weather events to the north or northeast.