Energy Content of Seeds of Switchgrass (Panicum virgatum) in the Diet of Mourning Doves (Zenaida macroura) in Southeastern New Mexico

Switchgrass (Panicum virgatum) is a common forage plant that grows over much of the United States. It has drawn interest as a possible feedstock for biofuels, is used as forage for livestock, is planted for soil conservation, and is a component of the diet of some species of wildlife. We analyzed the energy content of seeds of switchgrass obtained from the crops of mourning doves (Zenaida macroura) collected from plains-mesa sand-scrub in Lea and Eddy counties, New Mexico. Seeds were removed from crops and dried for 48 hours at 60°C to remove moisture and standardize masses. Seeds were then analyzed for gross caloric value (i.e., energy content) in an oxygen bomb calorimeter. Energy content of seeds of switchgrass from New Mexico averaged 18.4 J/kg (4.4 kcal/g—standard deviation, 0.7 J/kg [0.2 kcal/g]) and was lower than that of most other food items previously reported from the diet of mourning doves

Energy Content of Seeds of Palmer’s Pigweed (Amaranthus palmeri) in the Diet of Scaled Quail (Callipepla squamata) in Southeastern New Mexico

Palmer’s pigweed (Amaranthus palmeri) is a common grassland plant that occurs across much of North America. It is often considered a weed but is an important source of food for many game birds. We analyzed the energy content of seeds of Palmer’s pigweed obtained from the crops of scaled quail (Callipepla squamata) collected from plains-mesa sand-scrub habitat in Eddy and Lea counties, New Mexico. Seeds were dried for 48 hours at 60°C to remove moisture and then analyzed for gross caloric value (i.e., energy content) in an oxygen bomb calorimeter. Energy content of seeds of Palmer’s pigweed from New Mexico averaged 16.6 J/kg (4.0 kcal/g), and was among the lowest values obtained when compared to those of many seeds previously reported from the diet of scaled quail and other granivorous birds