CONCLUSIONS
While many of the statistical correlations and mapped observations were intuitive based on common characteristics of these 14 species, there were some exceptions. Some of the results of this study provide interesting insights and contrasts between species that are not intuitive. The combination of mapped locations of the birds and statistical analysis to determine habitat variables important to each species provides important conservation management information.
Prairie Warbler and Common Yellowthroat observations illuminated an important feature of the Sweet Briar property, which is increasingly a characteristic of landscapes over the entire Eastern United States; namely the lack of scrub habitat. Human land use has virtually eliminated this habitat type from the landscape. Species that use this habitat may be in decline because humans have systematically eliminated scrub habitat. Distribution of the Yellow-billed Cuckoo at Sweet Briar may be influenced by this lack of scrub habitat as well.
Several species analyzed do not adapt well to human disturbance, in particular, Ovenbird, Worm-eating Warbler, Acadian Flycatcher, Yellow-billed Cuckoo and Hairy Woodpecker. Conservation management for these species would entail preserving habitats in which they are currently found (Figures 3, 5, 11, 12 and 15). Other species, Wood thrush, Downy Woodpecker and Eastern Wood Peewee appeared to be adaptable to human disturbance. These species are not likely to decline as a result of selective land development. Many of the species that seemed amenable to human disturbance, however, are also dependent on forest reserves as habitat. Common Yellowthroat and Prairie Warbler also seem adaptable to human disturbance since they were found in "disturbed" scrub areas. At the same time this adaptability may reflect the limited scrub habitat at Sweet Briar rather than a tolerance of human activity.
Very few Brown-headed Cowbirds were observed, which may suggest that brood parasitism has not played a large role in any past declines of Neotropical migrants. This finding, however, is inconclusive because sample sizes were too small to draw statistically significant conclusions.
More analysis should be done to clearly define relationships between presence or absence of bird species and human disturbance variables. Quantification of landscape scale human disturbance variables using GIS would provide data for this analysis. These variables would include distance of observation point to roads, human structures and different land cover types, isolation of the habitat type. In addition, a more accurate and detailed classification of land cover types would aid in identification of habitat types and interpretation of bird distributions. Comparison of these data with historical bird survey data may provide information on population trends for these birds. This information could be very useful in identifying populations in decline that may warrant special attention in conservations management.
Introduction Methods Results and Discussion Conclusions Literature cited
