Brown Pelicans, Pelecanus occidentalis californicus (Aves: Pelecanidae): Five decades with ENSO, dynamic nesting, and contemporary breeding status in the Gulf of California

Review article/Articulo de revision Ciencias Marinas (2017), 43(1): 1–34 http://dx.doi. org/10.7773/cm.v43i1. 2710 Brown Pelicans, Pelecanus occidentalis californicus (Aves: Pelecanidae): Five decades with ENSO, dynamic nesting, and contemporary breeding status in the Gulf of California Pelicano pardo, Pelecanus occidentalis californicus (Aves: Pelecanidae): Cinco decadas con ENOS, anidacion dinamica y estatus contemporaneo de reproduccion en el golfo de California Daniel W Anderson 1,2 *, Carlos R Godinez-Reyes 3,4 , Enriqueta Velarde 5 , Rosalia Avalos-Tellez 3 , David Ramirez-Delgado 3 , Hugo Moreno-Prado 3 , Thomas Bowen 6 , Franklin Gress 2 , Jesus Trejo-Ventura 7 , Lindsay Adrean 8 , Lorayne Meltzer 8 Department of Wildlife, Fish, & Conservation Biology, University of California, Davis, CA 95616, USA. California Institute of Environmental Studies, 3408 Whaler Ave., Davis, CA 95616, USA. Area de Proteccion de Flora y Fauna, Islas del Golfo de California, Comision Nacional de Areas Naturales Protegidas, domicilio conocido, CP 22980, Bahia de los Angeles, Baja California, Mexico. Parque Nacional Cabo Pulmo, Comision Nacional de Areas Naturales Protegidas, Santa Maria la Ribera s/n, CP 23570, La Ribera, Baja California Sur, Mexico. Instituto de Ciencias Marinas y Pesquerias, Universidad Veracruzana, Hidalgo 617, Col. Rio Jamapa, CP 94290, Boca del Rio, Veracruz, Mexico. Department of Anthropology, California State University, Fresno, CA; Current Address: 28 Pinto Lane, Lander, WY 82520, USA. Area de Proteccion de Flora y Fauna, Islas del Golfo de California, Comision Nacional de Areas Naturales Protegidas, Calle Isla del Peruana esq. Isla Rasa s/n, Col. Lomas de Miramar, CP 85450, Guaymas, Sonora, Mexico. Waterbird Monitoring Program, Prescott College Kino Bay Center for Cultural and Ecological Studies, 220 Grove Ave., Prescott, AZ 86301, USA. * Corresponding author. E-mail: dwanderson@ucdavis.edu A BSTRACT . The California Brown Pelican subspecies (Pelecanus occidentalis californicus) was removed from the US endangered species list in 2009, along with the entire species of Brown Pelican throughout North America. The Gulf of California subpopulation within the entire metapopulation (= subspecies) comprises the majority of nesting (~76% of P. o. californicus). The US classifications were based on pollution effects in the Southern California Bight (SCB) during the early 1970s; official listing-recognition in Mexico (NOM-059-SEMARNAT-2010) occurred in 2010 and it continues. Unfortunately, Brown Pelican conservation across the US/Mexico border has been largely uncoordinated. Recent declines in the SCB subpopulation are not well-documented, whereas representative subpopulations in the Gulf of California have received continual study since the US listing. Until the early 2000s, Gulf pelican breeding populations changed little. El Nino/Southern Oscillation continues to be a major factor driving annual pelican breeding intensity and success, with a slightly weaker effect to the north. Nest attempts (NA) in the southern Midriff zone and to the south of our monitoring zone have declined in the last decade, in especially extreme and unprecedented ways in a period of unusual warming in the last 3 years (2014–2016), termed by some as the “Blob”. Other factors (such as human disturbance and commercial fishing) have likely exacerbated recent warming effects in some areas. Recent data also suggest the pelican is in a process of minor range-shifting toward the northern Gulf, and there are no definitive indications of a recent NA decline in that zone. Monitoring over the entire range, past 2016, will be important to determine whether populations have begun a long-term decline or will recover to normal baseline levels. The health of pelican populations is an important indicator of overall ecological health in the Pacific region and not an isolated phenomenon. Key words: California Brown Pelican (Pelecanus occidentalis californicus), conservation, current status, Gulf of California, ecosystem health. R ESUMEN . La subespecie Pelecanus occidentalis californicus (pelicano pardo de California) se elimino de la lista de especies en peligro de los Estados Unidos en 2009, junto con el resto de la especie en todo Norteamerica. La subpoblacion del golfo de California, incluida en la metapoblacion (= subespecie), comprende la mayoria de la poblacion anidante (~76% de P. o. californicus). Su inclusion en la lista de especies en peligro de los Estados Unidos se baso en los efectos de la contaminacion en la bahia del Sur de California a principios de la decada de los anos setenta; su inclusion en la lista oficial de Mexico en 2010 (NOM-059-SEMARNAT-2010) aun continua. Las acciones de conservacion del pelicano en ambos lados de la frontera entre Mexico y Estados Unidos no han estado coordinadas. Disminuciones recientes en la subpoblacion de la bahia del Sur de California no han sido bien documentadas, mientras que las subpoblaciones representativas del golfo de California han