resulted in estimates of breeding air max 2011

Wysłany: Nie 11:55, 20 Mar 2011

Radio-telemetry data on Mexican spotted owls from studies in Arizona, New Mexico, Colorado, and Utah resulted in estimates of breeding season home ranges that varied from 563 to 1,[link widoczny dla zalogowanych],250 acres (228-506 ha),[link widoczny dla zalogowanych] while nonbreeding season home range estimates varied from 902 to 2,540 acres (365-1,028 ha). In a ponderosa pine-Gambel oak forest of Arizona, nonbreeding home range size were significantly (P=0.008) larger than breeding home ranges [24]. However, in the Sierra National Forest there was an interaction between cover type and season on California spotted owl territory size, such that nonbreeding territories were larger than breeding territories in mixed-conifer forest but smaller in oak/pine woodland [60].
Other sources of variability in home range size include habitat requirements and prey availability. Spotted owls likely require a certain amount of old-growth forests. A literature review states that a pair of northern spotted owls uses an average of 2,000 to 2,500 acres (10 km2) of old-growth forests [55]. In areas where this resource is clumped and abundant, spotted owl home ranges are generally smaller. For example,[link widoczny dla zalogowanych] in coniferous forests in southwestern Oregon, northern spotted owl home range size varied from 1,320 acres (533 ha) in clumped mixed-conifer forest to 7,190 acres (2,908 ha) in fragmented Douglas-fir forest [10]. Several articles[32][58] note the inverse relationship between home range sizes and the amount of old growth within them. Spotted owls also require less area in certain cover types[16][40][60]. For instance, Mexican spotted owl home ranges in the Sacramento Mountains of New Mexico dominated by mixed-conifer forests were significantly (P<0.04) smaller than those dominated by ponderosa pine forests and pinyon-juniper woodland. In addition, home range size was inversely related (P≤0.003) to the amount of mixed-conifer forest in the home range [40].[link widoczny dla zalogowanych] The variation between different habitat types may be related to the availability of spotted owl prey [10][32]. For instance, the low numbers and inconsistent availability of prey on Washington's Olympic peninsula was suggested as a cause for the large northern spotted owl home ranges in this region [32].