Abstracts

Return to Conservation Biology Research on Birds

Belmonte, L.R. 2005. Home range and habitat characteristics of boreal owls in northeastern Minnesota. M.S. Thesis, University of Minnesota. 56 pp.

Abstract - Chapter 1: HABITAT CHARACTERISTICS OF BOREAL OWL SINGING AND CAVITY LOCATIONS IN NORTHEASTERN MINNESOTA

Habitat characteristics surrounding 42 Boreal Owl (Aegolius funereus) singing locations located between 1987 and 2001 through nocturnal surveys in northeastern Minnesota were examined. Vegetation was sampled at 0.04 ha plots surrounding each Boreal Owl song perch and one paired random plot located within the same stand. The majority (93%) of song perches were located in coniferous tree species. Boreal Owl singing locations had higher basal area, higher percent coniferous canopy and a taller overstory canopy compared with random locations. Using Landsat Thematic Mapper (TM) satellite imagery, the proportion of 13 land cover classes within 100 m (3.13ha), 500 m (78.14 ha), 1000 m (312.57 ha), 2000 m (1,256.27 ha), and 5000 m (7,814.17 ha) radii concentric circular plots surrounding cavity trees (n = 31) were compared with random locations (n = 41) distributed throughout the Superior National Forest. Lowland conifer, hardwood and mixed hardwood, upland conifer; ericaceous brush, sphagnum, open water, and roads were significantly different (P < 0.05) at all buffer levels between cavity and random locations. Classification and regression tree models (CART├?┬«) showed the landscape mosaic surrounding Boreal Owl cavity sites changes at varying spatial scales. Upland mixed forests were more common at cavity sites compared with random sites, particularly within 100 m of cavity trees. Upland conifer stands were more common at cavity sites compared with random sites at the 500 m buffer. Lowland conifer stands and ericaceous shrubs were more common surrounding cavity locations, especially at larger landscape scales (>1000 m).

Abstract - Chapter 2: HOME RANGE AND HABITAT USE BY MALE BOREAL OWLS IN NORTHEASTERN MINNESOTA DURING THE BREEDING SEASON

I used radiotelemetry to monitor the movements of three male Boreal Owls (Aegolius funereus) in northeastern Minnesota from April ├?┬? August of 2000-2001. Using Landsat Thematic Mapper (TM) satellite imagery, proportions of 13 land cover types within Boreal Owl home ranges were compared with proportions available throughout the study area. Both the Minimum Convex Polygon (MCP) method and the Fixed Kernel Method were used to estimate home range size. Home range estimates were based on both diurnal and nocturnal relocations. The mean 95% MCP was 607 ha (range = 430 ├?┬?931) while the 95% Fixed Kernel Method mean was 582 (range 407 ├?┬? 864). The majority of foraging locations occurred in heterogeneously mixed conifer and mixed coniferous-deciduous habitats.

Full document (995 KB) This is a PDF file. You will need Adobe Acrobat Reader to download it.