Incubation Behavior and Temperatures of the Mallard Duck

Abstract

THE natural incubation environment of wild Mallards (Anas platyrhynchos) has received little deterministic study. Prince et al. (1969a) considered the general effect of temperature and humidity under artificial conditions upon Mallard embryos. Batt and Cornwell (1972) intensively investigated the effect of cold on Mallard embryos, while Snart (1970) studied the upper thermal limits of Mallard embryos. They found Mallard embryos much more tolerant of cold than of heat. The above research employed artificial incubation and environmental chamber treatments. The present study was undertaken to describe more adequately the natural incubation environment of Mallard eggs and the hen behavior that produces this environment. Incubation behavior has been more thoroughly studied in avian species other than waterfowl. The incubation period is divided into attentive and inattentive periods which are related to species and clutch size (Skutch 1962). Incubation behavior and attentiveness are also affected by external stimuli (Kossack 1950, Kropivniui 1968, Barry 1962). Kendeigh (1952) reviewed the general daily rhythm of attentiveness to the nest by Anatids. Semenov-Tyan-Shanski and Bragin (1969) studying incubation behavior of Green-winged Teal (Anas crecca) and Common Goldeneye (Bucephala clangula) found the duck spent 1/7 to 1/8 of the incubation period off the nest. Cooper (1976) in an intensive study of Canada Goose (Branta canadensis) breeding behavior, found the female spent 98.5% of the incubation period on the nest. Kossack (1950) reported egg wetting in Canada Geese but the function of such behavior is unclear. McKinney (1952) described Mallard behavior patterns resulting in egg movements. Drent (1970) found Herring Gull (Larus argentatus) eggs maintained relatively constant orientation to gravitational forces, but they were frequently moved by the adult. Egg turning by the Wood Duck (Aix sponsa), a cavity nester, occurred about once a day (Stewart 1971). Temperatures of naturally incubated bird eggs and nests have been investigated frequently, but little work has been done with waterfowl species. Egg temperatures were recorded for the Canada Goose (Kossack 1947, Cooper 1976) and Wood Duck (Breckenridge 1956).