Cougar Predation

[Balam]

Cougar Kill Rate and Prey Composition in a Multiprey System, by Knopff et al.

ABSTRACT 

Assessing the impact of large carnivores on ungulate prey has been challenging in part because even basic components of predation are difficult to measure. For cougars (Puma concolor), limited field data are available concerning fundamental aspects of predation, such as kill rate, or the influence of season, cougar demography, or prey vulnerability on predation, leading to uncertainty over how best to predict or interpret cougar–ungulate dynamics. Global Positioning System (GPS) telemetry used to locate predation events in the field is an efficient way to monitor large numbers of cougars over long periods in all seasons. We applied GPS telemetry techniques combined with occasional snow-tracking to locate 1,509 predation events for 53 marked and an unknown number of unmarked cougars and amassed 9,543 days of continuous predation monitoring for a subset of 42 GPS-collared cougars in west-central Alberta, Canada. Cougars killed ungulates at rates near the upper end of the previously recorded range, and demography substantially influenced annual kill rate in terms of both number of ungulates (subad F (SAF) 5 24, subad M (SAM) 5 31, ad M 5 35, ad F 5 42, ad F with kittens ,6 months 5 47, ad F with kittens .6 months 5 67) and kg of prey (SAF 5 1,441, SAM 5 2,051, ad M 5 4,708, ad F 5 2,423, ad F with kittens ,6 months 5 2,794, ad F with kittens .6 months 5 4,280). Demography also influenced prey composition; adult females subsisted primarily on deer (Odocoileus spp.), whereas adult males killed more large ungulates (e.g., moose [Alces alces]), and subadults incorporated the highest proportion of nonungulate prey. Predation patterns varied by season and cougars killed ungulates 1.5 times more frequently in summer when juveniles dominated the diet. Higher kill rate in summer appeared to be driven primarily by greater vulnerability of juvenile prey and secondarily by reduced handling time for smaller prey. Moreover, in accordance with predictions of the reproductive vulnerability hypothesis, female ungulates made up a higher proportion of cougar diet in spring just prior to and during the birthing period, whereas the proportion of males increased dramatically in autumn during the rut, supporting the notion that prey vulnerability influences cougar predation. Our results have implications for the impact cougars have on ungulate populations and have application for using cougar harvest to manage ungulates.

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This is one of the most comprehensive and detailed studies made on cougar predation in a region rich in ungulate diversity, to begin with, the study shows a table of the most common prey items for cougars across different North American sites:

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Mule deer and elk were the most common prey items all across the board, trumping smaller game like white-tailed deer in preference. In Florida, alongside WT deer, feral hogs made up the main prey items for cougars, while in the study in question WT, mule deer, and moose were the main prey items.

Average weight of the prey items recorded in the study by sex and age:

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Predation rates of cougars divided by sex and age, notice how for adult males moose, deer (WT and mule), and feral horse were the main prey items in that order.

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Predation on adult moose and horse was relatively small, but the largest killed specimens weighed over 400 kg, representing less than 2% of the kills, while adult moose and horse, in general, made up 14% of the kills:

*This image is copyright of its original author

*This image is copyright of its original author

*This image is copyright of its original author

*This image is copyright of its original author

As adult males targeted larger ungulates than females, their kill rates were lesser as they would spend more time feeding on one large kill:

*This image is copyright of its original author

*This image is copyright of its original author

*This image is copyright of its original author

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This study highlights once more the tendency of cougars punching way above their weight class when it comes to the prey they target, with the juvenile large ungulates preferred by males averaging over 200 kg, more twice the size of average males in Alberta, and going as high as over 400 kg for the rare adult moose and horses killed as well, nearly 5 times their size. Reply