The Colorado River delta supports over 300,000 wintering waterbirds and is a critical stopover site for over 100 species of Neotropical migratory landbirds. This wetland system also provides habitat for significant populations of endangered species, such as the Yuma Clapper Rail and the California Black Rail. The goal of this project is to continue the implementation of a multi-species avian monitoring program in the Colorado River delta. The program is designed to detect trends in populations and vital rates of focus avian groups that will help guide management and restoration efforts in the delta. Major components of the program include marshbird surveys, bird banding to monitoring migratory landbirds, a MAPS station, and point counts in the riparian areas. The program has a robust scientific support, but also includes a strong community component, by training and including local residents as part of the monitoring team. Specific objectives include: (1) detect significant changes in bird populations in the delta region; in particular marshbirds, migratory landbirds, and riparian songbirds; (2) monitor vital rates (productivity and survivorship) of riparian songbirds; (3) associate these changes (if any) to changes in habitat features and management activities; (4) provide data for the long-term evaluation of effectiveness of the conservation, management, and restoration strategies; (5) contribute this information to regional and continental analyses of bird population trends; and (6) develop a strong community participation in the monitoring efforts.
Accomplishments to Date
- Annotated checklist of birds, including their status and phenology, in the Colorado River delta.
- Information on population trends of Yuma Clapper Rail and California Black Rail in the delta. This information was used to list the California Black Rail as Endangered in Mexico and update the status of the Yuma Clapper Rail (changed from Endangered to Threatened), provided a basis to update the Management Plan of the Upper Gulf of California and Colorado River Delta Biosphere Reserve, set management guidelines for the Ciénega de Santa Clara and El Doctor wetlands, and provided feedback and evaluation of the restoration efforts in the Rio Hardy.
- Information on the breeding status of the Yellow-billed Cuckoo and the Southwestern Willow Flycatcher in the delta.
- Information on the abundance, diversity, distribution, habitat affinities, vital rates, and temporal patterns of riparian birds in the floodplain of the Colorado River in Mexico. This effort included monthly surveys at 240 point counts during 15 months and a MAPS station. This information is providing basis for a conservation plan for the Colorado River in Mexico, which will include the allocation of an environmental instream flow.
- Information on the patterns of species richness, abundance, and temporality of Neotropical migratory landbirds using the Colorado River delta as a stopover site. We have captured, banded, and processed 2,308 birds from 63 species. This information has been sent to the Bird Banding Laboratory of the USGS, and also shared with other institutions working on regional analyses of bird migration. The collected data have provided new insights on landbird migration through the Sonoran Coast and the Upper Gulf of California region, as well as information on stopover ecology of landbirds in desert wetlands, and new bird records for the region.
- All the bird data were used to develop a Bird Conservation Plan for the Colorado River Delta.
- The bird data and bird records have been integrated into a relational database, and also integrated into layers of the Colorado River delta Geographic Information System.
- We have conducted two training workshops in bird monitoring techniques (April 2002 and March 2003), with the support of Point Reyes Bird Observatory. The workshops have provided training for 11 Mexican biologists and 4 community members of Ejido Luis Encinas Johnson. The workshop included training in bird identification, bird banding and processing, the implementation of several monitoring protocols (point counts, area searches, Southwestern Willow Flycatcher surveys, Yellow-billed Cuckoo surveys, and marshbird surveys), and data gathering, compilation, and analysis.