Sooty Tern
Description
The sooty tern (Onychoprion fuscatus) is a seabird in the family Laridae. It is a bird of the tropical oceans, returning to land only to breed on islands throughout the equatorial zone.
O. f. nubilosus flying on Rodrigues Island in the Indian Ocean
Distribution & Habitat
The Sooty Tern occurs through the tropical oceans of the world
(Oberle 2018, Raffaele and others
1998). In the West Indies, it is
generally a common breeding
resident from May to August
(Raffaele and others 1998). It is
fairly abundant in Puerto Rico
during the summer months
(Biaggi 1997), and it can be seen
on the nesting colonies in Mona,
Monito, and Culebra, as well as
the Cordillera Natural Reserve
(Oberle 2018). It is also found on
Vieques, where it is considered
an extremely rare summer visitor (Gemmill 2015). It mostly
occurs far offshore (Raffaele
and others 1998), except when
nesting (Oberle 2018). The atlas
fieldwork yielded a total of 24
records within 14 hexagons or 3
percent of the 479 total hexagons
(see map). Of the 14 hexagons
where this species was founds,
breeding met the atlas definition
of confirmed in 43 percent (six)
of the hexagons and possible
in 7 percent (one), while the
species was observed in 50
percent (seven) of hexagons but
without evidence of breeding
(see map).Sooty Tern distribution. The map shows the highest breeding code by hexagon and overlaying the ecological life zones in
Puerto Rico. Note: percentages may not total 100 due to rounding. 117Sooty Tern/Charrán Oscuro
Breeding Habits
Previously published reports indicate that the Sooty Tern
breeds from April to August
(Raffaele and others 1998). The
nest is a scrape made on coral
rubble or below overhanging
vegetation, mostly in large and
gregarious colonies (Raffaele
and others 1998). Atlas results
show that this species breeds
from March to July (see chart).
The breeding activity peaks
in June and takes place in the subtropical dry forest life zone
(see chart). Results show that this
species breeds in coastal areas
within the subtropical dry forest
life zone (100 percent of the
hexagons) (see table and map).
Conservation
The current overall population trend of the Sooty Tern is
described as unknown, as some
of the populations are decreasing
and others are increasing or
have unknown trends (Delany and Scott 2006). This species
is currently listed as a species
of least concern by the IUCN
(BirdLife International 2018).
Locally, this species is not
listed in any of the threatened
categories of PRDNER and
USFWS. In Puerto Rico, the Sooty
Tern has a protected habitat in
land of 2 percent or 3 km2 of the total area covered by the
hexagons where evidence of
breeding was found for this
species (167 km2).
Related Species
Family:
gull