boobies are chocolate brown above and white bellied as adults. The
brown extends down to upper breast and has a clear-cut division.
Smaller than Masked Booby, Brown Boobies are 25-29 inches, 64-74 cm in
white belly. Strong demarcated separation of brown and white plumage
across lower breast. Plumages of sexes generally alike but females have
greater mass than males.
with underparts usually mottled brown and white. Demarcation across
lower breast still apparent. These feathers shift to pure white over
the first two years. Could be confused by inexperienced observers with
immature Northern Gannets, or the other species of boobies.
recognized. Sula l.
leucogaster is the only subspecies in Atlantic
Basin. Appears to be little gene flow between island groups.
nesting colonies, with individual non-breeding birds often seen within
other seabird colonies.
distribution, Nominate subspecies endemic to tropical Atlantic; breeds
in the West Indies region, islands in the western Gulf of Mexico, and
in the tropical Atlantic (Cape Verde, Ascension and islands off
Brazil). Possibly nested formerly in Florida Keys.
distribution primarily restricted to Caribbean and Gulf of Mexico and
tropical Atlantic. This booby stays in the proximity of its breeding
sites throughout the year. Storm blown individuals and vagrants
occasionally along Southeastern Atlantic coast of United States.
closer to shore than other boobies, focus feeding in areas where
nutrients concentrate. Diurnal. They feed by plunge diving (from 1-15 m
above surface) and eat mostly flying fish and squid. Frequently in
mixed species flocks and over foraging predatory fish (jacks or tuna).
Follow fishing vessels to scavenge, or to capture fishes avoiding
wakes of boats, often landing on rigging.
Nest on the
ground; today normally restricted to rocky cliffs, isolated cays and
similar coastal predator-free sites. Like other boobies their nesting
season varies from site to site. This is a result of seasonal food
availability in adjacent waters and choosing nesting periods outside
the hurricane season. Long lived; 26+ years (banding record of
individual banded as adult). Life expectancy is 30-50
years. Defends territory within 1-5 m of nest. Constructs nest of
available materials, often lined with finer vegetation. Egg pale bluish
or greenish with chalky white outer layer. Clutch size 1-2, but only
one chick is reared. Incubation 40-44 days.
Fledging 95-120 days
based on food availability. Continue to be fed by parents while
learning to feed.
9784 Pairs in
the Region with large concentrations in the Bahamas, the central
Antilles, and islands of Venezuela and Colombian control within the
Caribbean. Central American estimates are minimums because we have not
received recent data.
Turks and Caicos
US Virgin Islands
British Virgin Islands
Antigua and Barbuda
St. Vincent and the Grenadines
Trinidad and Tobago
population considered vulnerable, few nesting sites are protected, and
loss of one or two of the larger breeding sites would represent an
important segment of the existing population. Extirpated from numerous
former nesting colonies. Considered Vulnerable (Schreiber and Lee 2000)
and declining in West Indies.
published biological studies have been conducted in
other portions of the species range so little is known concerning local
breeding phenology or dispersal.
is somewhat paradoxical that boobies, known for their tameness, are
actually quite vulnerable to human disturbance. To some degree it is
this very tameness that encourages people to enter colonies and closely
approach nesting birds. For unprotected nesting sites educational
signage explaining the fragile nature of seabird nesting colonies,
their importance and their vulnerability to disturbance would be
helpful. Conservation programs, laws and enforcement are badly needed
in the West Indies.
trend of decreasing populations for all West Indies boobies suggest
that all known colonies need to be protected and closely monitored.
Goats and development are major conservation issues. Egging and human
predation of adults still an issue in Jamaica. Major nesting sites need
protection and, in that this boobies often nest in association with
seabirds, this protection would cover a number of at risk populations.
Many colonies would benefit from regular patrols and key nesting
islands should have seasonal wardens to prevent disturbance or the
establishment of fishing camps.
colonies need to be identified by the individual governments and be
given permanent protection from future development.
2000. Status of Red-footed, Brown and Masked Boobies in the West
Indies. Pages 46-57 in E.
A. Schreiber and D. S. Lee (eds.) Status and
Conservation of West Indian Seabirds. Society of Caribbean Ornithology,
Special Publication Number 1. 225 pp.
E. A. and R. L. Norton. 2002. Brown Booby (Sula leucogaster). In The
Birds of North America, No. 649 (A. Poole and F. Gill, eds.) The Birds
of North America, Inc., Philadelphia.
Indian Breeding Seabird Atlas by Will
Mackin and David Lee is licensed
under a Creative
Commons Attribution-Noncommercial-No Derivative Works 3.0 United States
License. Based on
work at www.wicbirds.net.
Permissions beyond the scope of this license may be available at www.wicbirds.net.
Citation: Lee, D. S., W. A. Mackin. 2009. Brown Booby. West Indian
Breeding Seabird Atlas
<http://www.wicbirds.net/brbo.html>. Last Updated: _____.
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