Chufa (Cyperus esculentus) management and use by migratory birds in the middle Rio Grande Valley, New Mexico

Natural wetlands provide food resources for a variety of migratory birds. Although much is known regarding the production of aboveground food resources, comparatively less is known regarding the production of underground food resources such chufa (Cyperus esculentus") tubers. In addition, studies demonstrating the utilization of underground food resources by migratory birds are lacking. In 1996 and 1997, chufa tuber production and use by migratory birds were compared among mowing, discing, and sustained flooding treatments at Bosque del Apache National Wildlife Refuge, New Mexico. In addition to chufa, Johnson grass (Sorghum halepense), field bindweed (Convolvulus arvensis), and total underground production were compared. Aboveground plant composition, standing crop, and seed mass were also compared among treatments. Finally, the utilization of underground food resources by waterfowl and sandhill cranes (Grus canadensis) during winter flooding was measured by comparing paired open and exclosed sampling points in each treatment.