Philip N. Lehner

Coyote vocalizations: A lexicon and comparisons with other canids

Abstract Vocalizations of free-ranging and captive coyotes ( Canis latrans ) were recorded from January 1972 through August 1975. A lexicon of 11 vocalizations was constructed based on their: (1) sounds as perceived by the observer, (2) behavioural context, and (3) physical characteristics as determined through sound spectrographic analysis. The suspected functions and relative intensities of communication of the vocalizations are described. Comparisons are made with the vocalizations of other canids.

Risk-prone foraging behaviour in captive grey jays, Perisoreus canadensis

Abstract Grey jays were allowed to forage in a two-patch, closed-economy laboratory operant simulation of bark-gleaning foraging behaviour. Each patch exhibited identical mean variable ratio schedules (prey densities) but differed in variances around the mean. Four prey densities were used, ranging from very high density to a density demonstrated to provide a negative energy budget. Jays that did not develop side biases consistently foraged in high variance patches, exhibiting risk-prone behaviour. Time of day did not influence risk-sensitive foraging patterns. Several possible explanations for this behaviour are explored including body size, closed economy effects and the influence of the perception of prey value discounted by delay.

Conditioned avoidance in coyotes: Effects of administering LiCl during selected phases of the predatory sequence

Nine coyotes (Canis latrans) were tested for conditioned aversions to killing rabbits after lithium chloride (LiCl) was injected during three phases of the predatory sequence: approach, capture, and consumption. No long-term aversions were demonstrated following injections during the approach and capture phases. Aversions to killing rabbits lasted up to 20 days following injection during or shortly after the consumption phase.

A comparison of predatory behavior between prey-naive and prey-experienced adult coyotes (Canis la trans)

Three adult prey-naive and three adult prey-experienced coyotes were individually presented adult rats to determine the relative roles of prey experience and maturation in prey killing and consumption. The prey-naive coyotes individually played with and eventually “accidentally” killed the rats but did not consume them. When paired, the prey-naive coyotes competed for the rats, killed them, and tore them open, exposing flesh and stimulating consummatory responses. All three prey-naive coyotes learned to kill and consume rats in the social context and later performed the behavior as individuals. The experienced coyotes quickly killed and consumed rats in a species-typical manner as individuals during their initial and subsequent two trials. It was demonstrated that play with prey is necessary for speciestypical prey killing to develop, even in mature coyotes.

Serial reversal learning in the mallard duck (Anas platyrhynchos)

Serial reversal learning problems have been used primarily with the pigeon to develop theories of learning for the class Aves as a whole. This experiment tested the mallard duck and employed a procedure similar to that used for the pigeon. Five mallard ducks were tested in a visual discrimination task in daily sessions, with the rewarded symbol changed every 20 days. Improvement in the performance of the ducks did not occur to the same degree as that reported for the pigeon, and no evidence was found for a weakening of retention over time.