Caspian tern (Sterna caspia)
CONFIRMATION STATUS: Confirmed.
IDENTIFICATION
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Length: 20 inches Wingspan: 53 inches
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Sexes similar
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Dives into water for prey
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Large, barrel-chested tern with long, thick, reddish bill
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Short, notched tail
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Hints of a crest at the rear of the head
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Pale underwings with dark patch in primaries
Adult alternate:
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Deep red bill, often with indistinct black ring at tip
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Black legs
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Black cap with very slight crested appearance
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White face, neck, breast, and belly
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Pale gray back and upperwings
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Pale underwings with dusky gray on outer 5-6 primaries
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White tail
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Takes three years to reach full adult plumage
Adult basic:
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Similar to adult alternate, but has a black cap streaked with white and darker, more worn, primaries
Juvenile:
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Pale legs
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Deep orange bill
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Brownish cap streaked with white
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Upperwing coverts and scapulars marked by crisp, black scalloping
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White face, neck, breast, and belly
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Pale upperwing has darker outer primaries and secondaries
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Grayish tail
Immature:
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First-year birds are like basic-plumaged adults but have darker upper surfaces to the outer primaries, dark secondaries, a grayishtail, and a pale forehead
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Second-year birds are almost identical to alternate-plumaged adults, but have often white spots in the cap, darker outer primaries and some gray in the tail
Similar species:
When trying to identify terns, it is safest to use a combination of field
marks instead of relying on a single field mark. The royal and elegant terns
are the only other large, orange-billed terns and are quite similar. Elegant
terns are very small compared to Caspians, are very slim-winged, have
slimmer orange bills, have much more forked tails and less black on the
undersurface of the primaries. The Caspian can be separated from the
royal by its thicker, reddish bill, dark wedge on the outer portion of the
underwing, more shallowly-forked tail, broader wings and its tendency to
have an almost complete cap in basic and immature plumages. The smaller
sterna terns have slimmer, black or black-tipped bills, slimmer bodies and
wings and a much more deeply-forked tail.
LIFE HISTORY
Migration Status:N/A
Breeding Habitat:Wetland-open water
Nest Location:N/A
Nest Type:N/A
Clutch Size:1-4
Length of Incubation: 20-22 days
Days to Fledge:30-40
Number of Broods:1
Diet: Almost exclusively fish; lesser quantities of aquatic invertebrates
SKY MEADOWS DISTRIBUTION/SEASONAL OCCURRENCE
Relative abundance and seasonal occurrence are indicated in red below.
Relative abundance
C - Common: Likely to be present in good numbers in appropriate habitat and season.
U - Uncommon: May be present in appropriate habitat and season, often in low
numbers.
O - Occassional: Found in appropriate habitat perhaps only a few times per season,
sometimes low numbers.
R - Rare: May not be recorded every year.
Acc - Accidental: Recorded once or twice, may not be expected again for a long time.
Seasonal Occurrence
Sp - Spring: March, April, May Acc
Su - Summer: June, July, August
Fall: September, October, November
Winter: December, January, February
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