BIRDS: ISLA GUADALUPE

* 2001 Sweet, Paul R. et al. Recolonization of the Flicker and other notes from Isla Guadalupe, Mexico in Western Birds 32(1):72-80, 2001

"During a visit to Isla Guadalupe from 31 May to 3 June 1996, we documented three species new to the island, the Barn Owl, Swainson's Thrush, and Hooded Oriole, and established first breeding records for the European Starling and Western Meadowlark. Red-shafted Flickers are now breeding on the island, representing a recent recolonization from the mainland following the extinction of the endemic population. We investigated the validity of Colaptes auratus rufipileus and concluded that it doesn’t meet the standard for phylogenetic species but differs from C. a. collaris at the 75% level usually associated with subspecific rank. Damage to the cypress forest by goats continues, and all species dependent on these trees are threatened by loss of habitat."

* 2006 Quintana-Barrios, Lorenzo & G. Ruiz-Campos Update on the Birds of Isla Guadalupe, Baja California in Western Birds 37:23-36, 2006

* 2014. Hernández-Montoya, Julio C.; Luna-Mendoza, Luciana; Aguirre-Muñoz, Alfonso; Méndez-Sánchez, Federico; Maria Félix-Lizárraga, Maria; and Barredo-Barberena, J. M. Laysan Albatross on Guadalupe Island, México: current status and conservation actions in Monographs of the Western North American Naturalist: 7(1): Article 38.

"Guadalupe Island, off the Baja California peninsula, México, hosts the most important growing Laysan Albatross (Phoebastria immutabilis) breeding colony in the eastern Pacific. Since this seabird’s first arrival in 1983, it has been affected by predation from feral cats (Felis catus), present on Guadalupe since the late 19th century. Heavy predation events have been recorded on the island, so we initiated a feral cat control campaign in 2003 and began collecting baseline information for developing an eradication plan. At the same time, we conducted seasonal monitoring of Laysan Albatross reproductive success in order to assess the benefits from control activities. Cat relative abundance on Guadalupe was estimated through spotlight surveys, and control was done at the southernmost end of the island around the 2 locations where Laysan Albatross nest: Colinas Negras and Punta Sur. Laysan Albatross population growth rate was calculated based on the number of reproductive individuals, while breeding success was estimated as the proportion of laid eggs that resulted in fledged chicks. A total of 203 cats were removed from the south end of Guadalupe between 2003 and 2013. During this same period, high reproductive success (0.8) was recorded for Laysan Albatross, suggesting a positive effect of cat control activities. We found significant differences in reproductive success between years with predation and no predation by feral cats. The Laysan Albatross colony on Guadalupe has grown steadily during the past 30 years, increasing from 4 to 143 breeding pairs between 1984 and 2013, respectively, and with a population growth rate of 1.10 between 2004 and 2013."