This monitoring, which we carry out together with UABCS, is aimed at detecting population changes in shorebirds and migratory birds, as well as possible threats to their habitat. It is conducted every two years as a part of a continent-wide effort for wetlands in the Pacific.
In recent decades, there has been a verifiable degradation and, in some cases, loss of wetlands on the American Pacific coast. This problem is associated with human activity and factors like climate change, which causes a gradual increase in sea levels.
Waterfowl, including the shorebirds, ducks, and seabirds that inhabit wetlands, represent one of the most affected groups, with serious deterioration in their nesting, passage, and wintering sites. In fact, several species of shorebirds, such as the Kentish Plover (Charadrius alexandrinus), the Long-billed Curlew (Numenius americanus), and the Red Knot (Calidris canutus), have seen their population decrease.
Diagnostic and conservation actions for wetlands are essential and arise from adequate periodic monitoring of birds, an activity underscored decades ago by environmentalists such as Aldo Leopold, who in 1933 stated, “continuous censuses constitute the rule by which conservation success or failure is measured.”
For this reason Pronatura Noroeste and the Bird Laboratory of the Autonomous University of Baja California Sur (UABCS) successfully conducted last January a bi-annual monitoring of birds in the region’s primary wetlands. It is an intense task that was made possible thanks to the support of the David and Lucile Packard Foundation. For two weeks, a team of 18 people (in four simultaneous brigades) toured 17 wetlands for monitoring: Ensenada de La Paz, the Bahía Magdalena Complex, the San Ignacio Complex, the Guerrero Negro Wetland Complex, the San Quintín Lagoon Complex, the Upper Gulf and Colorado River Delta, Bahía de Lobos, Bahía de Tóbari, the Yavaros-Moroncárit Lagoons, Ohuira, Lechugilla, San Ignacio-Navachiste, Bahía Santa María, Ensenada Pabellones, Ceuta Beach, the Huizache-Caimanero Lagoon System, and Marismas Nacionales.
In this way, we generated information about the number of shorebirds that use each wetland. By comparing the data with those obtained in previous seasons, it is possible to evaluate population trends and to detect events of habitat loss and other possible threats. This activity is part of the Pacific Americas Shorebird Conservation Strategy, included in the Strategic Plan for the Conservation of Shorebirds and Ducks in Northwest Mexico, as well.
The identification and mass counting of birds was carried out by experts, who work with the help of binoculars and telescopes. Different types of vehicles were used to visit the sites, including boats, cars, ATVs, amphibian boats, and airboats, and in some cases, the tour was completed on foot.
An important thing to point out is that the Northwest represents the most important area for shorebirds in Mexico, due, in part, to its geographical location, since it is located in the transition between the Nearctic and Neotropical ecoregions. For some birds, the wetlands in the northwest of the country represent the southern end of their migratory route; others use them as a necessary step to migrate to more southern regions. In total, the region’s wetlands serve as breeding, wintering, or transit areas for at least 47 species of shorebirds, including some identified as priority species. Among the shorebirds with the highest population proportion in our wetlands, the Marbled godwit (Limosa fedoa), the Short-billed dowitcher (Limnodromus griseus caurinus), and the Pacific Red knot (Calidris canutus roselaari), which gather up to 70% of their individuals here, stand out. Other notable species are the American Oystercatcher (Haematopus palliatus frazari) with 65%, the American Avocet (Recurvirostra americana) with 40%, and the Western Sandpiper (Calidris mauri) with 20%.
The data we obtained in the monitoring will be shared with government agencies to develop actions aimed at wetland conservation. This will have a direct impact on the care of the birds that inhabit and visit our region, which require wetlands with optimal conditions to feed, grow, and reproduce.
