Foraging habitats of the seabird community of Europa Island (Mozambique Channel)

Sebastien Jaquemet

We investigated the foraging habitats of the
winter breeding community of tropical seabirds from
Europa Island (Mozambique Channel) in September
2003. We focused our study on the dominant species of
this austral community, the sooty tern (Sterna fuscata),
the red-footed booby (Sula sula), and the frigatebirds,
including the great (Fregata minor) and the lesser frigatebirds (F. ariel). We considered the at-sea distribution and abundance of these species in relation to
chlorophyll concentration, sea surface temperatures,
sea surface height anomalies, depth of the thermocline,
distance to the colony, and presence of surface marine
predators, flying fishes and other seabirds. Although the
marine environment where seabirds foraged was oligotrophic,
it presents the best feeding opportunities for
seabirds for the area in winter.


Our study demonstrates
that the winter-breeding seabird species of Europa Island
tend to forage in productive waters in association
with other marine predators when possible. Sooty terns
and frigatebirds were widely distributed in the whole
study area, whereas red-footed boobies were not found
farther than 160 km from their colonies and were associated
with relatively productive waters. Sooty terns and
red-footed boobies were aggregated where flying fishes
were abundant. The presence of other marine predators
was associated with larger multispecies feeding flocks
than when no association occurred. Sooty terns, which
are numerically dominant at Europa and adopted network
foraging, seem to be catalysts of feeding events, and represented a good target for the other foraging
species, especially frigatebirds. However, when possible,
frigatebirds favor association with flocks of red-footed
boobies.

We studied the at-sea distribution and abundance
of the seabird species that breed during the
austral winter on Europa Island in relation to physical
and biological factors. We tested how the different
species distributed themselves within their foraging
range and whether specific locations aggregate foraging
seabirds. We also examine the foraging strategies
adopted by each species, particularly the importance of
local enhancement on the feeding activity of the seabirds.

[2020-09-30] The following invalid species names were corrected according to the Integrated Taxonomic Information System (ITIS).
Sooty Tern: Sterna fuscata (176894) => Onychoprion fuscatus (824105)

Overview

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Attributes described below represent those in the original dataset provided by the provider.
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Attributes in dataset

Attribute (table column)	Description
oid	Unique ID number (generated by SEAMAP)
obs_date	Observed date
obs_time	Observed time
latitude	Latitude of observation
longitude	Longitude of observation
sp_obs	Species observed
sp_tsn	Species ITIS TSN
obs_count	Number of animals observed
transect
obs_number
id
behavior	vd: vol direct = flying, ep: en pêche = fishing, po: posé = sitting on the water
notes	notes on sex and age
poissons	fish sightings
mammiferes	marine mammal sightings