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Search for Craveri’s Murrelet (Synthliboramphus craveri) nests on the Eastern Midriff Islands

Project Description

The Craveri’s Murrelet is a small seabird that is considered quasi-endemic to the Gulf of California. They are the only species of Alcid in the Gulf and they are the southern-most member of their family. The Midriff Island region of the GOC is supposedly the nesting location of >95% of their population, which is estimated at 5,000 breeding pairs, ~21,000 individuals. Because of the nesting habits of this species, they are assumed to be highly sensitive to introduced predators (rats, mice, cats, goats, etc). Only a handful of studies have looked at Craveri’s Murrelets, and most of the literature published about the breeding of the species is more than 40 years old. The objective of this study is to document nest site locations and characteristics for Craveri’s Murrelets in the Sonoran Midriff Islands. If nesting sites are known, further study of nesting habits and biology can take place (either by PC or other institutions). In addition, if nest sites are identified, CONANP can adapt their management strategy to best protect the birds.

Project Results

In the spring of 2009, we conducted a basic nest search around the perimeter of Isla Alcatraz. This was done on three occasions for two hours each, covering 75% of the suitable nesting habitat. Eight Craveri's Murrelet nests were discovered in this time period. These are the first confirmed nests in the eastern Midriff Islands in over 30 years and make Isla Alcatraz the largest know nesting site for Craveri’s Murrelets in the world. The time between hatching and fledging was recorded for one nest. This was the second documented fledging time taken of this species. 

To further identify locations and characteristics of Craveri’s Murrelet nests we conducted searches on Islas Alcatraz, San Pedro Mártir, Dátil (Turner), Cholludo, Tiburon, Patos, and San Esteban, between mid-February and April 2010. A total of 14.3 km of coastline, making up five percent of the total coastline, was covered and 43.75 man-hours were spent searching for nests. Three islands, Islas Alcatraz, Cholludo, and Dátil, had nests from either 2009 or the previous year, with 14, 1, and 1 nests found respectively.

Reports & Publications

  1. Hurley, E., & Blinick., N. S. (In Prep). Fledging chronology and behavior of Craveri's Murrelets (Synthliboramphus craveri) on Isla Alcatraz, Gulf of California, Mexico

  2. Research and Conservation Program Report (2007-2011). Prescott College Kino Bay Center for Cultural and Ecological Studies