Energy-Based Carrying Capacity for Quails

Algorithms for estimating the carrying capacity of areas provide wildlife managers with important information for understanding and managing populations. Based on energetics of northern bobwhites (Colinus virginianus) and metabolizability of their foods, I develop a general, energy-based model for carrying capacity of quails (standard quail-yr/ha-yr) and show how to apply the model in management. A standard quail-year represents the number of quail-days accumulated anmially by a stable population that averages 1 bird/ha on 1 October. Analysis reveals that (1) the daily energy demand for movement (walk, run, fly) is minor in comparison with the demand for thermoregulation; (2) stable populations of northern bobwhites have similar quail-day accumulations for 1 year under expected variation in hatching dates and survival rates; (3) the concept of food quality as energetically based cannot be decoupled from time, because foods with different metabolizable energy values provide equal total energy if foraging time is adjusted; and (4) variable apportionment of time to foraging and nonforaging activities may have minor effects on survival rates, especially when density-dependent processes operate. The carrying capacity model suggests food plots may provide inconsequential additions to energy-based carrying capacity under typical intensity of application.