The ‘guano of the islands’ in Perú is the excrement of cormorants, boobies and pelicans (guano birds), accumulated in large deposits on islands and headlands. This guano is harvested and marketed by the governmental agency AGRORURAL to meet the demands of local organic agriculture. As part of its management and commercialization plans, AGRORURAL estimates the total quantity of guano built-up on the seabird colonies using a volumetric method. The objective of this research was to propose an alternative geostatistical method that uses the volumetric data collection as baseline but incorporates the slope of the terrain and makes estimations of the total amount and distribution of guano using an interpolation grid model in a Geographic Information System (GIS). The data of the slope of the terrain, depth of guano layer, guano density and proportion guano/rock of georeferenced sampling p...

Severe tick infestation in seabird colonies causes discomfort in reproductive adults, offspring mortality, and nest abandonment. This study used time-lapse cameras to examine the relationship between Ornithodoros amblus tick infestation and Peruvian Booby Sula variegata nest abandonment in four locations along the Peruvian coast between August 2016 and November 2018. The percent occurrence of discomfort in nesting birds (preening and standing on the nest) recorded by the cameras was used as an indicator of tick infestation. The tick density insideand outside the abandoned colonies was also evaluated. In five of the six colonies, complete nest abandonment occurred over an interval of two to three weeks. The percent occurrence of discomfort behavior was exponentially related to the percentage of nest abandonment, indicating that reproductive failure was related to tick hyperinfestation. Th...

Background: Drones are reliable tools for estimating colonial seabird numbers. Although most research has focused on methods of improving the accuracy of bird counts, few studies have evaluated the impacts of these methods on bird behavior. In this study, we examined the effects of the DJI Phantom 3 drone approach (altitude, horizontal and vertical descent speeds) on changes in the intensity of behavioral response of guano birds: guanay cormorants (Phalacrocorax bougainvilli), Peruvian boobies (Sula variegata) and Peruvian pelicans (Pelecanus thagus). The breeding and non-breeding condition was also evaluated. Methods: Eleven locations along the Peruvian coast were visited in 2016-2017. Drone flight tests considered an altitude range from 5 to 80 m from the colony level, a horizontal speed range from 0.5 to 15 m/s, and a vertical descent speed range from 0.5 to 3 m/s. The intensity of th...

This study was supported by Fondo Nacio-nal de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FONDECYT–Perú) within the ‘‘Proyecto de Mejoramiento y Ampliación de los Servicios del Sistema Nacional de Ciencia, Tecnología e Innovación Tecnológica’’ [contract: 08-2019-FONDE-CYT-BM-INC-INV’’], and by the Programa Nacional de Innovación en Pesca y Acuicul-tura and the Universidad Científica del Sur through the project ‘‘Aves Marinas como Centinelas del Mar: Uso de video-cámaras/ GPS en piqueros para monitorear actividades pesqueras ilícitas en el Perú (PNIPA-PES-SIADE-PP-000169)’’.