Sensory Aspects of Foraging Behavior in the Least Weasel (Mustela Nivalis) (Prey Detection, Carnivora)

This study examines the manner in which adult least weasels (Mustela nivalis) hunt for prairie voles (Michrotus ochrogaster) in an indoor grassland in an attempt to investigate foraging behavior from the perspective of the predator's sensory abilities. Five least weasels were filmed while foraging within a 2.4 x 2.4 m grassland of durum wheat. Trials were filmed under daylight conditions and during manipulations designed to disrupt the weasels' perception of acoustic and visual cues from prey. The entire arena was filmed from above at a rate of one frame per second. The resulting filmed record was digitized using the GALETEA computer system and then orthogonalized into a rectangular coordinate system. Predator speed, prey speed, and the distance between predator and prey were calculated at each successive second during foraging trials. Individuals differed in virtually every measure of search and detection. One characteristic shared by four of five weasels, however, was the tendency to move much slower than average for one second every three to five seconds. The data indicated significant negative relationships between the probability of prey detection and prey speed, predator speed, and distance between predator and prey. Visual and acoustic cues each contributed to prey detection since manipulations designed to disrupt them each reduced the probability of prey detection. Olfactory cues also were used; weasels usually investigated prey trails encountered while foraging, regardless of the age of the trail. These findings suggest that least weasels can use a variety of sensory cues to locate prey. They also support the hypothesis that predators that slow down occasionally while searching ought to be those exhibiting a strong negative relationship between predator speed and the probability of detection.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Zoology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Gillingham, Bruce Joseph

• Biology, Zoology

Language dc:language

eng

Identifier

(UMI)AAI8701493

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/77674