Shriver et al. 1999 Grassland Bird Sites

Coverage name: gis/gom/habstudy/species/bird/song/sparrowf/magrassbuf83.shp

Geographic extent: Gulf of Maine

Scale:

Automation Agency: USFWS

Source of Data: Shriver, W.G., R.J. MacCulloch, and J.V. Wells. 1999. Grassland Birds Data Compilation Project for the Northeast U.S. (USFWS Region 5). USFWS, Hadley MA. Greg Shriver sent database of these data from which I ultimately generated NAD83 shapefile gis/gom/habstudy/species/bird/raptor/harriern/masgrass83utm.shp; see gis/gom/habstudy/species/bird/raptor/harriern/shriver_data.txt.

Description: initially generated points from database (mas93-97grasslandbirddata.dbf); dropped the ones with crude (~ one minute or worse) accuracy; then made into cover and projected to nad27 utm, selected those with - ( [Countspp] > 1) or ([Sumbirds] > 2 ).

Based on tables in the manuscript, to 3 decimal places, figure these points are accurate to .001 degree = .06 minutes = 3.6 sec - about 316 feet = 100 m. Since Greg Shriver says the points are centers of 100m circles, figure they should indicate grassland habitats within 100m error plus 50 m to edge of observation = 150 m radius buffer. Thus buffered at 150 m to create magrassbuf.shp. These polygons indicate areas of known value to grassland birds, and so were used to score field sparrow habitat value (even though field sparrows were not directly recorded in the database).

Data Restrictions:

Status:

Projection: NAD 83 UTM meters, zone 19

Format: shapefile

Keywords: field sparrow