•  
  •  
 

Abstract

The Magnificent Frigatebird Fregata magnificens (MaFr) is a tropical seabird species that is widely distributed along the mid-latitude coasts of the Americas. Historically, its most important breeding location has been Estero Las Tijeras in the Magdalena Lagoon complex (MLC), Baja California Sur, Mexico. Our recent data indicate a severe (~96%) population decline at this location. In 2002–2003, 33535 MaFr were counted in all of the MLC, and historical data (1985–1986) support the maintenance of consistently high numbers of MaFr in this region over time. Yet, MaFr abundance dropped severely—to ~1 200 individuals—in 2015. This low abundance persisted into 2017, when we recorded 1712 individuals; however, we also discovered two new breeding colonies in Baja California Sur. Thus, from 2015–2017, we estimated a total breeding population of ~1 300 pairs in all of Baja California Sur. The reasons for this apparent severe decline, however, remain unclear. Based on satellite images, we discovered a large decline of living mangrove (~70% loss of apparent surface area) in Estero Las Tijeras from 2003 to 2017. Given these apparent changes in breeding effort, local population size, and observed shifts in nesting substrate, and considering other factors such as human disturbance and food-supply changes that may affect MaFr populations, it is evident that more extensive and detailed monitoring and ecological study of MaFr populations is needed. This will make it possible to further define factors affecting this species’ status and will support science-based management strategies.

DOI

http://doi.org/10.5038/2074-1235.49.1.1395

Download

Share

COinS