Factors determining diet composition of the Montezuma Quail (Cyrtonyx montezumae) at the northern limit of its distribution

Investigating Montezuma Quail (Cyrtonyx montezumae) diet composition is fundamental for unveiling how ecosystem processes limit its population size and may provide relevant tools for the management of this species. Our objective was to determine winter diet composition of the Montezuma Quail from crops harvested during 8 hunting seasons (2007-2017) and its geographic variation in Arizona and New Mexico. In addition, we used beta regression analyses to determine the effect of environmental factors on Montezuma Quail diet composition. Acorns (Quercus spp.) and sedge rhizomes (Cyperus fendlerianus) were the most frequently found food items of Montezuma Quail crops studied in Arizona and New Mexico, respectively, followed by tepary beans (Phaseolus acutifolius), woodsorrel tubers (Oxalis spp.), and arthropods in both states. Wet mass of forage from individual quail crops was positively associated with time of day. Quail diet composition in Arizona and New Mexico was associated with geographic variation in mean annual precipitation for acorns and with mean annual temperature for sedge (Cyperus spp.) rhizomes and tubers, but other main food items were not associated with environmental factors. These functional relationships between these 2 food items and climatic variables suggest that Montezuma Quail diet composition has a large component subject to environmental control.