Flammulated Owl (Otus Flammeolus) Breeding Ecology in Aspen Forests of Northern Utah: Including Responses to Ski Area Development

Publication Date


Type of Culminating Activity


Degree Title

Master of Science in Raptor Biology



Major Advisor

Marc J. Bechard


A number of aspects of Flammulated Owl (Otus flammeolus) breeding ecology were studied in the aspen forests of northern Utah. The primary study site, Snow Basin, is undergoing heavy development in preparation for the 2002 Winter Olympic Games.

First, Flammulated Owl reproduction was measured to investigate possible impacts of Olympic ski area development. Flammulated Owls nesting near the development site fledged significantly fewer young than owls at the control site, and also differed compared to data from other Flammulated Owl studies. Reduced productivity was attributable to significantly lower hatching rates at Snow Basin. Ski area development as well as high levels of recreational use were the most likely causes of this reduced productivity, possibly causing incubating females to flush, resulting in egg mortality.

Second, an experiment was conducted to investigate possible impacts of artificial lighting on breeding Flammulated Owls. Flammulated Owls were observed foraging in and around lights, suggesting that lights did not have a negative impact. Feeding rates, development of young, and productivity were compared between lighted and unlighted nests and did not differ statistically.

Finally, because the habitat at Snow Basin is unique for Flammulated Owls, and because the population nests primarily in nest boxes, habitat characteristics were described and nest site preferences examined. Results suggested Flammulated Owls were not as limited by habitat type as previously thought.

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