Movement patterns of Peruvian Boobies off Isla Lobos de Tierra 2006
Carlos B. Zavalaga

Dataset credit

Carlos B. Zavalaga

Contacts

RoleNameOrganization 
Primary contact Carlos Zavalaga Universidad Científica del Sur

Citation

Abstract

GPS loggers and time-depth recorders were used to haracterize the foraging behavior of the sexually dimorphic Peruvian booby Sula variegata on 2 islands in northern Peru. We evaluated whether (1) its foraging behavior differed from tropical boobies and temperate gannets (the Peruvian boobies feed in areas of enhanced productivity and high fish density), and (2) females and males exploited different foraging habitats as a consequence of size dimorphism. Birds foraged only during daylight hours, 1 to 3 times a day, in trips of short duration (median = 1.8 h). Overall, 92% of the total foraging time was spent flying. They fed exclusively on anchovetas Engraulis ringens, which were captured in shallow dives (median = 2.5 m, max = 8.8 m) with a dive median rate of 11 dives h–1 (max = 37 dives h–1). The median foraging range was 25 km (max = 68 km), whereas the median total distance traveled was 69 km (max = 179 km). Foraging site fidelity was high, and the orientation of foraging flights in any given day was similar among birds that departed at the same time. There were no sex-specific differences in 13 of 15 foraging variables; however, females dived slightly deeper and spent a larger proportion of time sitting on the water. We speculate that (1) the foraging behavior of Peruvian boobies contrasts with that of their tropical and temperate relatives as a result of the proximity and predictability of food sources, elevated energetic demands of the brood (up to 4 chicks) and high prey encounter rate in the Peruvian upwelling system, and (2) the lack of spatial segregation between sexes may be related to the attraction of birds to feeding aggregations that are formed in the vicinity of the colonies. Once the foraging patches are localized, females dive deeper because of passive mechanisms associated with a heavier mass.

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Attributes

Overview

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Attributes in dataset provided

Attribute (table column)Description
oidUnique ID number (generated by OBIS-SEAMAP)
bird_idBird ID
obs_timeTime of observation in UTC
obs_dateDate of observation
longitudeLongitude in decimal degrees
latitudeLatitude in decimal degrees
sp_obsSpecies name recorded
sp_tsnTaxonomic Serial Number added by OBIS-SEAMAP
obs_countNumber of animals (always 1; added by OBIS-SEAMAP)
sexSex
age_classAge (always Adult)
weightWeight in grams
geomGeometry field added by OBIS-SEAMAP
OBIS-SEAMAP ID1104
Seabirds143,568
Marine mammals0
Sea turtles0
Rays and sharks0
Other species0
Non spatial0
Non species0
Total143,568
Date, Begin2006-12-22
Date, End2006-12-29
Temporal prec.111111
Latitude-6.71 - -6.10
Longitude-81.17 - -80.41
Coord. prec.6 decimal digits
PlatformTag
Data typeTelemetry location
TracklinesYES (ID: 1105)
Registered2014-02-05
Updated2014-03-04
StatusPublished
Sharing policy CC-BY (Minimum)
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1