AVIS-IBIS

Birds of Indian Subcontinent

Characteristics of Occupied and Unoccupied Loggerhead Shrike Territories in Southeastern Alberta

Publication Type:Journal Article
Year of Publication:1993
Authors:Prescott, DRC, Collister, DM
Journal:The Journal of Wildlife Management
Volume:57
Issue:2
Date Published:1993
ISBN Number:0022541X
Keywords:Laniidae, Lanius, Lanius ludovicianus
Abstract:Population declines in loggerhead shrikes (Lanius ludovicianus) are most frequently blamed on habitat limitation. Thus, we compared structural characteristics of loggerhead shrike territories in southeastern Alberta with characteristics of visually similar, but unoccupied, sites in the same area. We predicted that if reproduction in this threatened population is limited by habitat availability, then occupied and unoccupied sites should consistently differ along ≥ 1 structural dimension. Stepwise discriminant function analysis (DFA) identified 5 of 15 habitat variables that were potential discriminators (P < 0.05) of site occupancy by shrikes. Canonical DFA showed that these 5 variables discriminated between occupied and unoccupied sites with 98.4% accuracy. Occupied sites contained a higher percentage of tall (≥20 cm) grass, and had a higher mean height of grass than unoccupied sites. We suggest that loggerhead shrikes may be limited by habitat in southeastern Alberta, and that the availability of suitable habitat for breeding could be increased by management practices that increase the prevalence of tall grass.
URL:http://www.jstor.org/stable/3809432
Short Title:The Journal of Wildlife Management
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith