Wetlands in Northwest Mexico provide critical habitat for both migrating and resident shorebirds. Bahía de Ceuta (23°54’N, 106°57’W) is a coastal wetland with high biodiversity located in Sinaloa, Mexico. We monitored the nest habitat selection and reproductive success of three ground nesting bird species that use Bahía de Ceuta for reproduction: Snowy Plover Charadrius nivosus, Wilson’s Plover C. wilsonia and Least Tern Sternula antillarum. We found 34 Snowy Plovers nests, eleven Wilson’s Plover nests and monitored 31 Least Tern nests over the breeding season. Snowy Plovers used similar open nest habitats largely located on mud flats or sites with small pebbles. Wilson’s Plover pairs preferred nesting sites that were covered by halophyte vegetation. This year Snowy Plovers shifted the breeding area further North in comparison with previous years. Wilson’s Plover and Snowy Plovers had similar nesting success (36% and 38% of the nests hatched). Nesting success was much lower for Least Terns. Only 7% of the monitored nests hatched. The 2012 breeding season ended as a complete failure for the local Snowy Plovers. Nest number declined by 52% in comparison with 2011 and not a single chick fledged. The long drought period followed by erratic flooding led to the observed failure this year but the lack of necessary conservation management actions compounded the situation. In the past Bahía de Ceuta hosted one of the largest Snowy Plover populations and an important Least Tern colony at the Pacific but if no appropriate conservation measures are taken the breeding site may vanish within a few years.
Project Report: Severe Decline of Threatened Plovers at Bahía de Ceuta, Sinaloa, Mexico