Agenda - 09-29-1999 - 9e - Laserfiche WebLink

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APPENDIX I PRELIMINARY SURVEYS OF BIRDS IN ORANGE COUNTY FORESTS During the summer of 1998, Susan Campbell, an ornithologist who works for the N. C. State Museum of Natural Sciences, surveyed birds in forests in several areas of Orange County. The intent was to determine the species breeding in the different types of forest identified on the maps of forest in Orange County. There are nine such categores: hardwood, mixed, and pine forests, each undisturbed, slightly disturbed, and strongly disturbed by human activities. PROCEDURES The areas easily accesible for this work were, Moorefields Estate, Occoneechee Mountain, Duke Forest (Durham and Korstian Divisions), Pickard's Mountain, Cane Creek Reservoir, University Lake, and Mason Farm Biological Reserve. In each of these areas, she received enthusiastic cooperation from the resident owners or managers. Occurrence of birds was recorded during "point counts ", a standard procedure for assess- ing the occurrence and density of birds. During each point count, the observer recorded all birds seen or heard within 50 meters of an arbitrarily selected point located as much as possible within a larger area of one type of forest. Points were never closer than 100 meters apart, to avoid overlap in individuals recorded. All counts were conducted during the morning between 6:00 and 11:00 a.m. Altogether 84 point counts were obtained in May and June. The areas available for surveys provided fewer opportunities for studying disturbed forests than undisturbed ones. Consequently, most counts were obtained in undisturbed hardwood (31 counts), mixed (21), and pine (14 counts); there were 15 counts in slightly disturbed forests, and only 4 in strongly disturbed forests. Only the counts in undisturbed hardwood and mixed forests adequately sampled the birds. Most of the censuses in undisturbed pine forests were conducted in Duke Forest, where most tracts of uniform forest are small. Consequently, the counts in these forests often included some species from adjacent hardwood forests. There were too few counts in disturbed forests for firm conclusions. The data for these counts is on file in the office of the Triangle Land Conservancy. A summary of the results is presented here. GENERAL OBSERVATIONS It became clear that the County must update its maps of forests periodically. Campbell's notes repeatedly refer to recent loss of forest in the County. The maps do not reflect clearing for building since 1988 (although information about recent building permits indicates where such clearing has probably occurred). The maps also do not reflect clearing for timber sales. The State has information about timber sales in ArcInfo format, but the County has not yet been able to obtain this information. In addition, some areas designated on the maps as Mixed Forests are now nearly pure Hardwood. Campbell noted that Hurricane Fran had blown down pines in some areas of Mixed Forest and thus accelerated the final stage of succession to Hardwood Forest. Of course, some Mixed Forests on the maps just missed the crite- rion for Hardwood Forests in 1988 and subse- 19