Sampling & coverage
Each block consisted of 1/6 of a USGS 7.5 minute topographic quad. One priority block was randomly selected per quad. All 178 established priority blocks as well as additional special area blocks were surveyed.
View blocks in the Mapping Tool >>
Coordination of coverage
Management of this project was accomplished with the help of coordinators in 20 regions.
(see handbook for full description & use suggestions)
OB Category - Observed: not breeding evidence
Species (male or female) observed in its breeding season with no evidence of breeding. Not in suitable nesting habitat.
PO Category - possible breeding evidence
Species (male or female) observed in suitable nesting habitat during its breeding season.
Singing male, or courthip display of waterfowl or diurnal raptors.
PR Category - probable breeding evidence
Pair observed in suitable nesting habitat during its breeding season.
Territory presumed from observations of territorial behavior.
Courtship behavior or copulation.
Visiting probable nest site.
Agitated behavior or anxiety calls from adult.
Brood patch or cloacal protuberance.
Excavation of nest holes, or nest building by wrens.
CO Category - confirmed evidence of breeding
Distraction display or injury feigning.
Nest building by any species except wrens.
Used nest found. Must be carefully identified if it is to be accepted.
Recently fledged young.
Adult(s) entering or leaving nest site in circumstance indicating occupied nest.
Adults with fecal sac or food for young.
Nest with egg(s).
Nest with young seen or heard.
- - this atlas does not record habitat on the field card - -
Most of the information on this page is from
the project's publication or Handbook
(guide for field work).