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Bonaparte's Gull
(Chroicocephalus philadelphia)
 German name(s): "Bonapartemöwe"
Size: 31-34 cm; wing span: 79-84 cm
Weight: 180-225 g (males heavier than females)
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Similar
species |
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Physical description |
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 Click here for a physical description
Bonaparte's Gulls are small, slender gulls.
Except for the fact that males are a bit bigger and heavier than
females, the two sexes are identical. Both sexes have different
plumages during
the breeding season and in
eclipse.
In breeding
plumage, apart from
thin partial white eye-rings, Bonaparte's Gulls have a near-black,
dark-chocolate-coloured head. The short neck, the
entire front and the rump are white. Only the mantle and wings
are light-grey, with white outer primaries and black tips on the
primary flight feathers. The white tail has a black terminal band
on the upperside.
The short bill is black.
In
eclipse they loose their black cap, leaving just two black
spots on either side of the head, above and behind the eyes,
with the spots above the eyes being very inconspicuous.
In all seasons the wings protrude beyond the end of the tail.
The irises are dark. The short legs and feet are pink in
and orange-pink during the breeding season.
First-winter
Bonaparte's Gulls resemble adults in eclipse
plumage, but
with dark centres to the wing feathers.
Juveniles
have brownish tints on the head and on the wing feathers.
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Twitcher's tip |
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The easiest way of telling Bonaparte's Gulls apart from
Black-headed
Gulls is by the colour of the bill (Bonaparte's Gull has
a black bill) and by the length of the legs (Bonaparte's Gull
has short legs).
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Taxonomy, classification |
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See
Bonaparte's Gull at Wikipedia  .
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Range, habitat, finding this species |
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Click here for information on habitat
and range
The overall distribution of this species can be assessed, and
specific locations where birds have been spotted can be found,
based on individual sighting reports submitted by birdwatchers to
ebird.org
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The global distribution of Bonaparte's Gull is available
HERE
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Bonaparte's Gulls are a migratory species.
Their core range is the North-American continent.
Their breeding grounds lie in central and western
Canada and in Alaska, while they overwinter partly
in coastal areas (in the West of the continent they
are found ONLY along the coastline, from Washington
State, USA, in the North to Cabo Corrientes, Mexico,
in the South.
Along the East coast of the continent they overwinter
all along the coastline from Maine, USA, in the North,
to Florida, USA, Cuba, and northern Mexico in the South.
Bonaparte's Gulls overwinter also inland, from South
of the Great Lakes into the Mississippi/Missouri
catchment and all the southern states from Texas to
the Carolinas. For details see, e.g.,
Wikipedia
.
In Europe, Bonaparte's Gulls are found only as vagrants,
with a few records per year from the British isles and
rare appearances also along the West coast of Iberia.
They visit Europe only outside the breeding season and
are therefore always seen in
non-breeding
plumage.
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Sightings |
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Click here for sighting information
G. Pinelas reports finding Bonaparte's Gull at
Praia da Torre, Oeiras, Lisbon, Portugal, in March 2017.
All sighting and photographic information presented on this
page has kindly been contributed by G. Pinelas.
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Photos |
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ADULT |
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NON-BREEDING |
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Near-frontal view of Bonaparte's Gull in non-breeding
plumage;
note the black bill and the short pink legs
(photo courtesy of G. Pinelas)
[Praia da Torre, Oeiras, Lisbon, Portugal, March 2017]
Near-frontal view of Bonaparte's Gull in non-breeding
plumage
shaking out its feathers
(photo courtesy of G. Pinelas)
[Praia da Torre, Oeiras, Lisbon, Portugal, March 2017]
Lateral view of Bonaparte's Gull in non-breeding
plumage
(photo courtesy of G. Pinelas)
[Praia da Torre, Oeiras, Lisbon, Portugal, March 2017]
These pages are largely based on our own observations and those of our
contributors. The structure of these bird pages is explained HERE. For more salient facts on any bird species
please refer to a field guide.
Breeding
Nest
Eggs
Behaviour
Food
Call/s
