The Puerto Rico Breeding Bird Atlas (PRBBA) is a comprehensive survey project documenting the distribution and abundance of breeding birds across Puerto Rico. The goal of the atlas is to help guide conservation efforts and track population trends of Puerto Rico’s avifauna.
Background on the PRBBA
The idea for a breeding bird atlas in Puerto Rico was first proposed in the 1990s, but the project did not begin in earnest until the 2000s. The PRBBA is modeled after state breeding bird atlas projects in the continental United States, which systematically survey breeding birds in blocks of land across each state.
The Puerto Rico Ornithological Society led the effort to launch the breeding bird atlas. They partnered with various government agencies, universities, and non-profit groups to carry out fieldwork, analyze data, and publish the findings. Major funding came from the US Fish and Wildlife Service and the Puerto Rico Department of Natural and Environmental Resources.
Fieldwork for the first PRBBA lasted from 2004 to 2009. Over 100 volunteers conducted surveys in designated atlas blocks across Puerto Rico’s main island and adjacent islands like Vieques and Culebra. The findings were published in a book called Birds of Puerto Rico in 2010.
Atlas Field Methodology
The PRBBA divided Puerto Rico into over 300 atlas blocks, each about 25 square kilometers in size. Volunteers were assigned blocks and asked to carry out standardized surveys during the breeding season from January to June each year.
The main survey method was point counts. At each accessible point within the block, volunteers would stand still for 6 minutes and record all bird species seen or heard. Points were at least 250 meters apart and were located in representative habitats across the block.
In addition to point counts, volunteers documented breeding evidence for each species. Breeding evidence included things like courtship behavior, nests with eggs or chicks, adults carrying food, and juveniles begging from parents.
| Breeding Code | Evidence of Breeding |
|---|---|
| PO | Pair observed in suitable habitat |
| T | Permanent territory presumed through registration of territorial behavior |
| DC | Courtship and display |
| NN | Nest building or excavation of nest hole |
| ON | Occupied nest indicated by adult entering or leaving nest, incubating, or presence of eggshells |
| FY | Adult carrying fecal sac or food for young |
| NE | Nest with eggs |
| NY | Nest with young seen or heard |
| FL | Recently fledged young incapable of sustained flight |
| CF | Adult feeding fledged young |
Volunteers visited blocks at least twice during each breeding season and aimed to document as many species as possible across diverse times and weather conditions.
Key Findings
The first PRBBA documented breeding activity for 115 species, including migrants like the Black-throated Blue Warbler and endemic species like the Puerto Rican Tody. Some key findings included:
- 51 species were confirmed breeding on the offshore islands of Vieques and Culebra.
- Atlas blocks in karst forest regions had the highest bird diversity.
- Evidence of breeding was found for all 9 endemic Puerto Rican bird species.
- Certain widespread species like Bananaquits and Black-faced Grassquits were confirmed across nearly all atlas blocks.
- Endangered species like the Puerto Rican Parrot and Yellow-shouldered Blackbird had limited breeding distributions.
The Puerto Rico Ornithological Society published a book highlighting the major results of the project. Detailed breeding distribution maps were made for each species. The authors used the data to make recommendations for habitat management and conservation priorities.
Second Atlas
A second Puerto Rico Breeding Bird Atlas project launched in 2016 to resurvey the island and document any changes. This time, eBird and other technologies are being utilized to make data collection and analysis more efficient. The second atlas is set to run until 2022.
Comparing the second atlas to the first will reveal how breeding bird populations have shifted over the past decade. Researchers will be able to see if endangered species have declined and if any habitats need new protection. updating this valuable baseline data will help conservationists make informed decisions about Puerto Rico’s birds.
Conclusion
Breeding bird atlases provide crucial data on bird populations that can inform habitat management and species conservation. The Puerto Rico Breeding Bird Atlas revealed distributions and breeding trends for over 100 species across the territory. It set a baseline that the second atlas project will now build upon to track population changes. Data from breeding bird atlases helps ensure that all species, whether common or endangered, get the habitat protection and support they need.
