Skip navigation.
Virginia 1985-1989


General Methods
Sampling & coverage of blocks

The geographic unit of the Atlas project is the "quad block". These units are based on subdivisions of the USGS 7.5 minute quadrangles. Each quadrangle was subdivided into 6 rectangles of approximately equivalent area called quad blocks. Volunteers were asked to choose one Atlas "block" to survey during the breeding season for presence of breeding activity. To ensure that at least one block was thoroughly surveyed in each quad, the southeast block of every quad was designated as the "priority block". Volunteers were asked to survey the priority block if no other blocks could be surveyed.

View blocks in the Mapping Tool >>

Coordination of coverage
Virginia was divided into 12 regions with 25 regional coordinators.

Breeding Evidence Codes
Code Code description  (see handbook for full description & use suggestions)
OB Category - Observed: not breeding evidence
O Species (male or female) observed in a block during its breeding season with no evidence of breeding. Not in suitable nesting habitat. Includes species such as vultures or raptors flying over, or a colonial nesting species not at a nesting colony.
RC Raptor carrying food.
PO Category - possible breeding evidence
/ Species (male or female) observed in suitable nesting habitat during its breeding season.
X Singing male present in suitable nesting habitat during its breeding season.
PR Category - probable breeding evidence
P Pair observed in suitable nesting habitat during its breeding season.
S Permanent territory presumed through song at same location on at least 2 occasions 7 days or more apart.
T Permanent territory presumed through defense of territory (e.g. chasing individuals of the same species).
C Courtship behavior or copulation.
N Visiting probable nest site.
A Agitated behavior or anxiety calls from adult.
B Nest building by wrens or excavation of holes by woodpeckers.
CO Category - confirmed evidence of breeding
CN Bird carrying nesting material, such as sticks or other material. Please submit full details including location within the block of the observation.
NB Nest building at the actual nest site.
PE Physiological evidence of breeding, e.g. highly vascularized, edematous brood patch or egg in oviduct based on bird in hand. (For banders.)
DD Distraction display or injury feigning.
UN Used nests or egg shells found. Must be carefully identified, if they are to be accepted.
PY Precocial young. Flightless young of precocial species restricted to the natal area by dependence on adults or limited ability.
FL Recently fledged young (either precocial or altricial) incapable of sustained flight, restricted to natal area by dependence on adults or limited mobility.
ON Adults entering or leaving a nest site in circumstances indicating occupied nest. To be used for nests which are too high (e.g. the tops of trees) or enclosed (e.g. chimneys) for the contents to be seen.
CF Adult carrying food for young.
FY Adult feeding recently fledged young.
FS Adult carrying fecal sac.
NE Nest with egg(s).
NY Nest with young seen or heard.
Habitat Codes
- - this atlas does not record habitat on the field card - -

Where this information came from
Most of the information on this page is from the project's publication or Handbook (guide for field work).
U.S. Department of the Interior || U.S. Geological Survey || Patuxent Wildlife Research Center  Laurel, MD, USA 20708-4038
This site is:
Information contained in this application does not necessarily have the endorsement of USGS.

Last updated: Site - May 2014; Content - various, depending on atlas.
Page generated on: 27-Mar-2023