Breeding Bird Atlas

What is a Breeding Bird Atlas?

Grid-based atlases are efforts to document systematically the occurrence of plant or animal species within a given area. Two monumental efforts in Britain, Atlas of British Flora (Perring and Walters 1962) and Atlas of Breeding Birds in Britain and Ireland (Sharrock 1976), unleashed a plethora of projects around the globe including many in the United States and Canada.

The Florida Ornithological has been an integral partner in the only two Breeding Bird Atlases conducted to date in the state of Florida. The goal was to document the breeding birds across the state.

2012 – 2024

Florida Breeding Bird Atlas II (FL BBA II)

The Florida BBA II is a product of the Florida Ornithological Society (FOS) and hundreds of volunteers, working together and independently, based on a scientific survey design and in concert with the U.S. Geologic Service Patuxent Wildlife Research Center. Breeding bird population data allow comparison of current distributions to those recorded during the first atlas and with results in other states, potentially documenting range changes across the southeast U.S. This atlas was published as an FOS Special Publication and can be read online or in print.

Florida BBA II species accounts includes:


BBA I and BBA II species maps. Jim Cox has made BBA II maps for approximately 200 species. Comparison of BBA I and BBA II maps provides the basis of an evaluation of changes in breeding distribution over the 25-year period between the atlas efforts.
 USGS Breeding Bird Survey graphs for surveywide and Florida population trends.
Diane Pierce artwork (the same artwork as in BBA I) and additional species.
A brief (400 word) species account and population change evaluation.
An online version of BBA II thanks to a  collaboration with the University of South Florida Libraries.

Rick West initiated the effort, convincing FOS Presidents and leaders from Patuxent to begin breeding bird surveys across Florida, conducted by hundreds of FOS volunteer bird experts during the springs and summers of 2011-2016. Rick and Patuxent staff collected the data and Jim Cox created the maps showing, for each species, where birds were found nesting in both surveys.

 Special Publications Editor Ann Hodgson worked with a BBA II Committee consisting of FOS President Ann Paul, Jim Cox, Adam Kent, David Stock, Mary Mack Gray, and Todd Engstrom and oversaw the publication of the Florida Breeding Bird Atlas (BBA) II. Over fifty Florida bird scientists and experts wrote the individual species accounts. Florida bird artist Diane Pierce donated the use of her bird sketches from the BBA I and inked additional sketches for bird species that were not included in BBA I. She also donated original art of nesting Snail Kites in flight for the front page. University of South Florida Librarian Dr. Todd Chavez directed his staff led by Dr. Amanda Boscar who collated, formatted, and published the BBA II online in November 2023.

Draft species map of the American Crow by Jim Cox.

1986 – 1991

Florida Breeding Bird Atlas I (FL BBA I)

The first Breeding Bird Atlas was a collaborative effort headed by Audubon Florida in partnership with FOS and the Florida Fish and Wildlife Conservation Commission. Surveys for BBA I were begun in Spring 1985 and sightings of nesting activities were collected for five years. Volunteers visited atlas blocks and recorded the birds found there. The grids used to delineate atlas blocks were the 7.5-minute topographic quadrangle maps prepared by the U.S. Geological Survey. Each 7.5-minute quadrangle was divided into 6 equal-sized atlas blocks that encompassed about 10 square miles (25 square km). Florida is made up of approximately 6,234 atlas blocks, but not all blocks were visited. Due to the untimely death of the lead scientist, Herb Kale, publication was delayed but eventually the Atlas was made available to the public online by the Florida Fish and Wildlife Conservation Commission under the leadership of Karl Miller.

Atlas volunteers were provided a handbook describing data collection methods and were encouraged to locate every bird species breeding within their assigned block. Evidence of breeding was subdivided into 3 broad categories: POSSIBLE, PROBABLE, and CONFIRMED. The breeding evidence goes as follows:

POSSIBLE: species observed in breeding season in suitable habitat; singing male present or breeding calls heard in suitable nesting habitat but not in breeding season.

PROBABLE: pair observed in suitable habitat in breeding season; bird apparently holding or defending a territory or singing male present on at least two days, a week or more apart; courtship behavior or copulation observed; species visiting probable nesting site; agitated behavior or anxiety calls observed; brood patch observed; nest building or excavation of a nest cavity, or bird carrying nesting material observed; or seven or more territorial males in a block observed at least a week apart.

CONFIRMED: distraction display or adult feigning injury; used nests or egg shells found; female with egg in oviduct; recently fledged young observed; adult on nest or seen in circumstances indicating an occupied nest; adults carrying fecal sac or food; nest with eggs; or nest with young.

Illustration of a Yellow-crowned Night Heron by Diane Pierce, taken from the BBA I.

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