Aspects of nest site selection and habitat use by burrowing owls at the Rocky Mountain Arsenal, Colorado
Year: 1992
Type: dissertation
Abstract: The ecology of breeding burrow1ng owls (Athene \ncunicularia) was studied at the Rocky Mountain Arsenal (RMA) \nduring 1990 and 1991. Time-budgets of nesting burrowing \nowls were characterized for pre- and post-hatch seasons. \nMale and female adults differed (P < 0.05) in the amount of \ntime spent resting, alert, and out-of-sight in the pre-hatch \nseason. Pre- and post-hatch behaviors differed (P < 0.0001) \nfor both males and females. Male alert behavior decreased, \nwhile time spent out-of-sight increased from pre- to posthatch \nseasons. Female alert behavior increased, while outof- \nsight behaviors decreased from pre- to post-hatch \nseasons. Radio collared burrowing owls rested less (P < \n0.05), were alert less (P < 0.005), and out-of-sight more (P \n< 0.005) than non-instrumented birds. \nFood habits were studied by analysis of castings and \nprey remains found at occupied burrows. During both years, \n1,445 castings were dissected, and contained 1,703 prey \nindividuals. Burrowing owls failed to take insect families \nother than expected (P > 0.05) on the basis of availability. \nNesting burrowing owls occupied burrows with a shorter \ndistance to the nearest road, and shorter grass and forb \nheight (P < 0.005) than available, while selecting burrows \nwith greater burrow density, nearest-perch distance, and \npercentage of bare ground (P < 0.05) than available. Banded \nadults returned in 1991 at a rate of 38% (n=12). Of \nreturning adults, 66% (n=8) reused the same prairie dog town \nused the prior year. overall, dog towns had 90% reuse in \n1991 (n=17). \nBurrowing owls at RMA were sexually dimorphic. Males \nwere larger in tail and wing (P < 0.05) and tarsometatarsus \n(P < 0.0001) measurements, while females were heavier (P < \n0.05). No correlation (P > 0.05) was found in morphometric \nmeasurements of mated pairs (n=27). During both years, 56 nests were attempted. Brood size at fledging averaged 4.38 \nchicks/territorial pair. The only adult measurement \ncorrelated to productivity was female wing length (~ = .33, \nP < 0.05, n=36). Burrow attributes were correlated to \nproductivity only for tunnel convolution in 1990 (~ = .43, P \n< 0.05, n=24).
Author: David L. Plumpton
Language: English
Topic: Avian ecology and behavior
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: green
OpenAlex ID: W2800401904