Kelly, J. P., Roth, J. E.
We modeled temporal continuity and dispersion in the daily movements of resident common ravens (Corvus corax) in central coastal California and determined the extent to which the patterns varied within and between seasons and across diurnal periods. Raven locations generally became temporally independent within 2 h during the breeding season. In the non-breeding season, raven locations were temporally dependent for as long as 10 h and confounded by oscillations in average distance that suggested cyclically repeated behaviors. Ravens significantly clustered their home range locations within days during the breeding season, with daily geographic shifts accounting for 0-39% of breeding-season dispersion. Our results suggest that estimates of breeding-season home range size or habitat use by resident ravens should be based on observations, or groups of dependent observations, collected at least 2 h apart or at constant time intervals, sampled evenly among as many days as possible, and stratified intraseasonally to account for potential differences among nesting stages. During the non-breeding season, samples should be separated by at least a day or grouped into dependent daily samples with constant time intervals.
Kelly, J. P., and J. E. Roth. 2007. Spatial and temporal patterns of diurnal movement in Common Ravens. ACR Tech. Rpt. 98-9-5. Audubon Canyon Ranch, P.O. Box 808, Marshall, CA 94940.