SANDHILL CRANES IN THE MID·PECOS VALLEY OF EASTERN NEW MEXICO, 1989- 91

Weekly roost counts and observations of flock movements and field use were conducted during winters of 1989 -90 and 1990-91 to determine the status of sandhill cranes (Grus canadensis) in the RoswelllBitter Lake National Wildlife Refuge region of the Pecos River Valley of eastern New Mexico. Cranes roost on shallow lakes along the Pecos River, both on and off the refuge, and rely on approximately 36,000 ha of mostly irrigated farmland for foraging. During the past decade, alfalfa production has increased to 20,000 ha and corn production has decreased to 2,000 ha, of which 98 % is cut for ensilage to support an expanding dairy industry. About 600 ha are planted in sorghum. Fields of corn and sorghum stubble provide an important foraging resource, and alfalfa fields are also widely used by the cranes. Cranes numbers during the 1989 -90 wintering season peaked at 5,635 in early November, declined to an average of 3,180 during December and January, and increased to a spring peak of 4,800 in February. Roosting was evenly divided between the refuge and a site 15 km farther south. The foraging pattern generally matched the distribution of farmlands. During the 1990-91 wintering season, crane numbers peaked at 7,280 and averaged 6,100 through January without the late November decline observed during the previous year. Hunting in November 1990 apparently caused most of the cranes to abandon the off-refuge roost site and change their foraging pattern. Two-thirds of the cranes foraged from November through January in an area comprising only 15% of the total farmland