Nighthawk

Abstract: The family Caprimulgidae contains species which appear to deviate from general avian patterns in certain aspects of their physiology. Lesser Nighthawks (CtcordeiZes acuti@nnis) and Poorwills (PhaZuenopti2us nuttallii) can remain torpid for relatively long periods in a manner reminiscent of hibernating mammals (Marshall, 19 5 5 ; Jaeger, 1949; Thorburg, 1953). Pauraques (Nyctidromus aZbicoZZis) and Poorwills have lower basal metabolic rates than most birds of comparable size (Scholander, Hock, Walters, and Irving, 1950; Bartholomew, Hudson, and Howell, 1962). Most or all members of this family employ gular fluttering in their evaporative cooling, and this contributes to an unusually effective capacity for temperature regulation in hot environments (see Cowles and Dawson, 1951; Howell, 1959; Bartholomew, Hudson, and Howell, op. cit.). Although these features make caprimulgids of special interest from a physiological standpoint, only the Poor-will has been subjected to extensive experimental investigation (Bartholomew, Howell, and Cade, 19.57; Bartholomew, Hudson, and Howell, op. cit.; Howell and Bartholomew, 1959). Since studies dealing with the physiology of additional species in this group appeared desirable, this investigation of the effects of ambient temperature on oxygen consumption, heart rate, evaporative cooling, and body temperature of the Common Nighthawk (Chordeiles minor minor) was undertaken. This species, which is abundant in southeastern Michigan in summer, might be expected to differ from the Poorwill in certain features of its physiology owing to its larger size and more extensive distribution.

Abstract: Although the Common Nighthawk (Chordeiles minor) has been studied extensively, certain phases of its breeding biology have been considered only superficially. Among these are the incubation movements of the female, the manner in which eggs are moved, and certain activities of the male. An opportunity to investigate this behavior presented itself when a Nighthawk nested on the graveled roof of the Wildlife Building of the University of Missouri in 1957. I am indebted to Thomas S. Baskett, William J. Hamilton III, Frank McKinney, and Margaret M. Nice for assistance with the manuscript.

Abstract: Over one third of North American bird species are in decline, and for many species, we still lack fundamental biogeographic information such as migration routes and nonbreeding areas. Identifying c...