Auugst 2005

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In the Spotlight: Joint Efforts for the Restoration of the Colorado River Delta
(This column spotlights a different SJV-supported project each month. To submit information about your project, contact Jennie Duberstein.)

The Colorado River delta is one of the most important areas for bird conservation in the Sonoran Desert. The delta supports more than 210,000 migratory water birds each winter, is a critical stopover site for more than 100 species of Neotropical migratory landbirds, and provides habitat for protected species, such as the Yuma Clapper Rail and the California Black Rail. A binational team of environmental groups, universities, and government agencies is working in the conservation of remnant wetlands and the restoration of priority sites. The goal is to develop an economy based in the natural resources that facilitate conservation and improvement of ecological functions and that also provides opportunities to maintain cultural values and improve the quality of live of these communities. This initiative consists of multiple components, focusing on three principal objectives: 1) assignment of water for the environment, 2) long-term legal protection of wetlands, and 3) implementation of an adaptive management plan based in ecological values of the Colorado River delta.

In this context, bird conservation and monitoring projects have been essential en the development of strategies, evaluation of restoration actions, and as primary indicators of environmental health and completion of goals. These projects have been supported by the Sonoran Joint Venture and other partners, including the North American Wetland Conservation Act (NAWCA), the Upper Gulf of California and Colorado River Delta Biosphere Reserve, PRBO Conservation Science, the National Ecology Institute (INE), the Centro de Investigación en Alimentación y Desarrollo (CIAD), the University of Arizona, and the Instituto del Medio Ambiente y Desarrollo Sustentable del Estado de Sonora (IMADES). Collaboration with local communities has been en essential factor, as much with their involvement as resource users and landowners as with their participation as guides and field technicians, particularly with the community of Ejido Luis Encinas Johnson. Two people from the ejido form an integral part of the delta bird monitoring team.

During the past year, the main activities have consisted of mistnetting, capturing, and banding birds, including: monitoring wintering survival in restored riparian zones and undisturbed sites (a total of 4 sites); monitoring spring Neotropical migratory landbird migration en stopover sites in El Doctor, Río Hardy, and Río Colorado; and monitoring breeding/resident avian productivity and survivorship en riparian zones in the delta. These efforts indicated in 2002, with a sample of 3,210 net-hours/year, we have banded more than 5,000 birds. These efforts are complemented with point counts (4 times/year), en 144 variable distance points in the Colorado River delta in Mexico . Point counts have been conducted since April 2002, resulting in 220,000 bird observations. Additionally, we have conducted marshbird monitoring through tape playback surveys, following standardized protocols, en 150 points distributed in the marshes of the delta.

This work has permitted us to document the presence of 358 species of birds in the Colorado River delta and to follow population trends of protected species, such as Yuma Clapper Rail and California Black Rail, with estimated populations of 4,810 and 137 individuals, respectively, during 2004.

The monitoring program also has permitted us to understand and follow the avian community in restored riparian zones in the delta, where disturbances and the influence of valley agriculture are obvious, as is evident by the most common birds: Mourning Dove, Brown-headed Cowbird, and Red-winged Blackbird. Nevertheless, numerous species are common nesters in this area, uncluding Verdin, Abert's Towhee, Blue Grosbeak, Song Sparrow, Ladder-backed Woodpecker, and Crissal Thrasher. Some species have reestablished in the area recently and are now regular nesters, such as Osprey, Vermilion Flycatcher, Yellow-breasted Chat, Cinnamon Teal, and Lesser Goldfinch. Yellow-billed Cuckoo has also returned to the Colorado River delta with a small but regular population (7-10 pairs each summer).

During this process we have also documented the presences of species rare for this region, including Piping Plover, Alder Flycatcher, Gray Catbird, Blackpoll Warbler, Black-and-White Warbler, American Redstart, Northern Waterthrush, Ovenbird , Canada Warbler, Hooded Warbler, McCown's Longspur, Rose-breasted Grosbeak, Indigo Bunting, Baltimore Oriole, and Pine Siskin.

Despite its ecological importance, the lack of a secure source of water is still a serious threat for the Colorado River delta. Information generation about the status of birds has become an essential tool by providing critical information about changes in bird populations and habitats that is used to guide conservation efforts.

We are particularly working to develop a legal mark and to acquire water rights (through a voluntary program with farmers, based in the market), to secure a minimum flow for wetlands. We hope to complete the first water rights acquisitions en the fall of 2005. We are also working with federal and state government agencies to designate the Colorado River delta as a Federal Restoration Zone, with an Integral Restoration Plan, and to designate the river floodplain (federal zone) as a conservation easement. At the same time, we are also working on 5 restoration projects in the Río Hardy and the Laguna del Indio. Together, these projects cover approximately 790 ha do wetlands and mesquite bosque. Our goal is, through these efforts, we may extend a vision of a restored and ecologically-functional Colorado River delta that can provide benefits to birds, bird habitat, and communities, regardless of borders.

More information about these bird conservation initiatives can be found in the report on Conservation Priorities in the Colorado River delta and the Colorado River Delta Bird Conservation Plan.