Presented by Colorado Bird Atlas Partnership:

The Second Colorado Breeding Bird Atlas

Atlas Methods ~ Atlas Field Protocol

Surveying Blocks

Atlasers surveyed each habitat type within priority blocks in order to identify the species breeding in each block. We set goals for adequate coverage of priority blocks to insure thorough coverage. Upon meeting these goals, atlasers could move on to subsequent blocks. We set the following adequate coverage goals:

  • Cover all habitats
  • Spend ~20−40 hours in the block, depending on the variety of habitats
  • Confirm at least 50% of the species recorded in the block
  • Take at least one night trip for nocturnal species

While effort hours defined by adequate coverage goals applied to most priority blocks, some blocks had adequate coverage with fewer survey hours—those with only one or two habitats or low species richness (e.g., plains blocks with only prairie, cropland, and an occasional farmhouse and a few shrubland-only blocks in the San Luis Valley).

Breeding Criteria

Standard behavior criteria (used by Breeding Bird Atlases continent-wide) classified each species as Confirmed, Probable, or Possible breeders (see Breeding Codes). These data also contributed to defining the breeding phenology for most species.