Proportion Of Home Range Research Articles

Home Ranges and Movement Characteristics of Minks in East-central New York

Abstract Space use information for native minks (Neovison vison) along river systems is insufficient due to either low sample size or exclusion of tributaries that minks readily use. We compared linear home ranges for 23 minks and compared daily movement distances between the Hudson River and its tributaries for 33 minks. Mean home range proportion for 12 minks that used both the Hudson River ( = 2.7 km) and its tributaries ( = 3.0 km) was not significant. However, daily movement distances were significantly greater along tributaries ( = 732 m) than along the Hudson River ( = 532 m), which may indicate differences in prey density between each of the waterbody types. The mean home range for 11 minks that strictly used tributaries was 4.7 km and the mean overall home range (waterbody types combined) for all 23 minks was 5.2 km. There was a significant difference in home range size between males (5.8 km) and females (4.1 km). This study contributes to the relatively few available ecological studies o...

Home Range and Land Use of Urban Long-eared Owls

Abstract. From 2004 to 2006 we studied the spatial activity of Long-eared Owls (Asio otus) breeding in the city of Ceske Budějovice, Czech Republic. Two main factors (size and proportion of home range in developed area) clearly distinguished the owls into two groups: urban (n = 5) and suburban (n = 4). Urban owls occupied home ranges >50% in developed area; home ranges of suburban owls were <50% in developed area. We obtained 866 radio fixes from nine individuals while they were feeding offspring, when both males and females participated in hunting. The home ranges of urban owls were larger than those of suburban owls (95% kernels: 446 vs. 56 ha, respectively). Urban males and females used home ranges of similar sizes that overlapped greatly with those of the opposite sex and with those of other breeding pairs. In contrast, suburban male owls had home ranges larger than those of suburban females. Wooded areas and meadows were the vegetation types preferred by both urban and suburban owls, and both groups ...

A comparison of two home range modeling methods using Ugandan mountain gorilla data

Home range is the area over which animals traverse in the course of their normal daily activities. Home range measures are essential to understanding a species' behavioral ecology and can be critical information for biological conservation. In the realm of mountain gorilla (Gorilla beringei beringei) management at Bwindi Impenetrable National Park, home range is typically calculated using the minimum convex polygon (MCP) approach. However, geographic information system has enabled more robust measures of home range to be calculated from field data. In order to assess the potential utility of a new home range modeling method, local convex hull (LoCoH), we compared LoCoH home ranges with those derived from MCP for several different gorilla groups. First, we evaluated the sensitivity of each method to outliers. Second, we compared the size of yearly home ranges for groups with distinctively different ranging behavior. Third, we compared the proportion of yearly home range found outside the park for two different groups. As anticipated, we found that LoCoH ranges are smaller (∼50%) than MCP ranges, but contrary to expectation our data show that MCP is not more sensitive to outliers than LoCoH. Our comparison also illustrates that the two methods result in different proportions of home range found outside the park; overall, MCP had a tendency to underestimate relative to LoCoH. Our results illustrate the importance of selecting an appropriate home range model for the spatial pattern of the data being modeled, the environment and context where the data were collected, and the motivation of the research. Overall, we found LoCoH to be a more effective home range modeling method for mountain gorilla conservation management.

Factors Influencing Wild Turkey Hen Survival in Southcentral Iowa

A decline in the population of eastern wild turkeys (Meleagris gallopavo silvestris) in southcentral Iowa necessitated more current estimates of population parameters. Survival of 126 eastern wild turkey hens in southcentral Iowa was investigated during 1993-96. Estimates of annual survival averaged 0.676 ± 0.048% (x ± SE) for adults and 0.713 ± 0.125 for subadults. Mammalian predators, primarily coyotes (Canis latrans) and red fox (Vulpes fulva) accounted for 64% of all documented mortality. Age-specific annual survival distributions differed within years (P < 0.03), but no difference was detected in survival between age classes across years (P = 0.49). Based on chronological dates, survival of adult hens differed among seasons across years (P = 0.03). However, seasonal survival was not different when estimates were based on hen behavior (P = 0.48) Risk of mortality for hens increased by 2.0% for every 100-m increase in dispersal distance, decreased by 2.0% for every 10-ha increase in home range size, and decreased by 3.5% for each 1.0% increase in proportion of home range in woody cover. Although the exact cause of the population decline remains unknown, we sugges it was more likely related to a decrease in production than changes in hen survival. Declining turkey populations would likely benefit more from management designed to increase reproduction rather than hen survival.