Lane, W.H. 1989. 1988 and 1989 survey to determine the status and distribution of the boreal owl in Cook County, MN. Final report submitted to the Nongame Wildlife Program, Minnesota Department of Natural Resources. 5+ pp.
During 1988 and 1989, I conducted nocturnal surveys in Lake and Cook Counties of northern Minnesota to determine the number and locations of singing male boreal owls. Male boreal owls were identified at 37 locations in 1988, and 52 locations in 1989. Sites with male owls were revisited following completion of the evenings' surveys and foot surveys conducted to determine utilization of potential nesting cavities. Four cavities were located in 1988; 13 in 1989. All cavities occurred in mature-growth aspen. Two nest sites were documented in 1988 and three in 1989. Cavity tree parameters and cavity site habitat data were ascertained and are included in this report.