WBBA - Methodology

Methodology

Each 7.5 minute USGS topographic quadrangle in Wisconsin was divided into six blocks - NW, NE, CW, CE, SW, SE - each of size 5km x 5km (10 sq mi). Within a given block, atlasers recorded the breeding code of bird species detected, observation date, and optionally, habitat code and abundance code. Due to time constraints, it was not possible for atlasers to survey every block within a particular quad, thus the centereast block was designated the Priority Block. In order for the Atlas to be considered complete, the Priority Block must be surveyed for each quad. Additionally, there are 138 quads which contain one or more Specialty Blocks for which habitat information of each species observation was required.

Atlasers completed a new field card for every block they surveyed. The atlaser recorded the year, quad, block, whether the survey was at night, and the atlaser's name and address. A record of field visits was kept containing date of each survey trip, number of hours spent in the field each trip, total number of observers on each trip, total number of hours spent traveling to and from field sites, and total mileage. Additionally, atlasers completed casual observation forms to record species in blocks the atlaser was not surveying.

WBBA Species List - list of 236 species with Probable or Confirmed breeding status.
Wisconsin Birds Check List - complete list of 414 species ever recorded in the state; from the Wisconsin Society for Ornithology website.

The following Verification Forms are not online forms; once the form has opened, save form to your computer, print out, complete and send in by regular mail.

WBBA Verification Form (MS Word 6.0/95 format)
WBBA Verification Form (Word Perfect 6/7/8 format)

BREEDING CODE is based on increasing importance of breeding status:

Observed: (O) species observed in block but with no evidence of breeding.
Possible: (X) species encountered in suitable nesting habitat.
Probable: (M) multiple singing or territorial birds detected in block on one day.; (S) singing male at same location on at least two occasions a week or more apart.; (P) pair observed in suitable nesting habitat.; (T) defense of territory by fighting or chasing individuals of same species.; (C) courtship behavior or copulation.; (N) bird observed visiting likely nest side repeatedly.; (A) agitated behavior or calls from adults (indicating possible nest site or young in vicinity).; (B) nest building or excavation of cavities.
Confirmed: (PE) physiological evidence of breeding such as brood patch or egg in oviduct.; (CN) bird seen carrying nesting material such as sticks, grass, etc.; (NB) nest building observed at nest site (excluding wrens and woodpeckers).; (DD) distraction displays such as injury feigning.; (UN) used nest or eggshells found during Atlas period.; (ON) occupied nest indicated by adult entering or leaving nest site.; (FL) recently fledged dependent young.; (FY) adult carrying food for young or feeding recently fledged young.; (FS) adult bird carrying fecal sac.; (NE) nest with eggs or eggshells on ground.; (NY) nest with young seen or heard.

For a complete description of the breeding codes as defined in the Atlasing Handbook, refer to [Breeding Codes].

ABUNDANCE CODE represents the number of estimated breeding pairs in the surveyed block:

1 pair
2-10 pairs
11-100 pairs
101-1000 pairs
more than 1000 pairs

HABITAT CODE is based on a nested arrangement with four levels of increasing precision. The following indicates the first three levels:

Forest (greater than 50% tree cover)
Shrub/Savanna (greater than 50% tree cover with greater than 25% total cover of woody vegetation)
Open (less than 25% woody vegetation)
Urban/Rural
Special (to append to other habitat designations as necessary)

For a complete description of WBBA habitat codes, please see Habitat Codes.

Wisconsin Breeding Bird Atlas
wbba@uwgb.edu