Survey point characteristics

  • Latitude and longitude—You can determine latitude and longitude from a topographic map or the BFL mapping software found on our web site. Latitude lines run east to west; longitude lines run north to south. The best way to determine latitude and longitude is by using a Global Positioning System (GPS) receiver in the field or Geographical Information System (GIS). Refer to the References:Map Resources section of the manual for information on how to measure latitude and longitude from maps. GPS units can be purchased at sporting goods stores, or check with your site coordinator or local governmental agency to see if they have a unit you can borrow.

   • Elevation—Report the elevation above sea level at the survey point. You can determine elevation by carefully checking the contour intervals on a topographic map. Be sure to indicate units (feet or meters) on your data forms.

   If you use a GPS unit to calculate elevation, please check this number against measurements from a topographic map because GPS units are not always accurate for determining elevation.

   • Distance to nearest edge—Measure or pace the distance from the survey point to the nearest forest/nonforest edge of your patch (for large distances, measure from a map or aerial photo). A break in the forest that is 300 feet (90 meters) wide or more constitutes an edge (Figure 1). Indicate units.

   • Distance to nearest road—Measure or pace the distance from the survey point to the nearest road (for large distances, measure from a map or aerial photo). We define a “road” as a linear break in the forest canopy that is 25 to 300 feet (8 to 90 meters) wide (Figure 1). Please indicate units. The road may be dirt or paved, open to motor vehicles, or closed. For the purpose of this project, a power-line cut or other right-of-way that breaks the canopy is considered a “road.” Recent research suggests that the corridor created by even a small dirt road may allow cowbirds and predators access to the forest interior.

   • Distance to nearest water—Measure or pace the distance from the survey point to the nearest stream, pond, marsh, swamp, etc. (Figure 1). Indicate units.

   • Distance to nearest occupied building—Measure or pace the distance from the survey point to the nearest building that is occupied during the breeding season (Figure 1). Indicate units.