Mottled Owls (Ciccaba Virgata): Response to Calls, Breeding Biology, Home Range, and Food Habits

Publication Date


Type of Culminating Activity


Degree Title

Master of Science in Biology



Major Advisor

William Burnham


During April and May of 1989, mottled owls, Ciccaba virgata, were exposed to tape recordings of conspecific calls in Tikal National Park, Guatemala. Their responses were counted and the relationship between calling and certain parameters (such as weather, light, and time of night) was evaluated. The owls were quite responsive to broadcast of conspecific vocalizations throughout the study period. Wind was the only factor, of those tested, that affected the potential to hear an owl call. The high rate of response (40%) under a variety of conditions suggests that broadcast of taped calls can be used as a census tool for this species.

During the 1990 breeding season, seven mottled owl nests were found in cavities of live trees. Mean clutch size was 2.14. Five of these nests fledged a total of nine young, which left the nest at between 27 and 33 days of age. Mean home range size was 22.9 ha (85% harmonic mean) for four radio-tagged breeding males, and the density of this population was 7.5 breeding adults per sq km. The owls were quite vocal, and four distinct calls were heard. The diet was found to consist primarily of beetles and other insects, with cricetid rodents taken regularly as well. A large sexual size dimorphism, not previously described for this species, was observed.

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