Caspian tern (Sterna caspia)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CONFIRMATION STATUS: Confirmed.

 

IDENTIFICATION

  • Length: 20 inches Wingspan: 53 inches

  • Sexes similar

  • Dives into water for prey

  • Large, barrel-chested tern with long, thick, reddish bill

  • Short, notched tail

  • Hints of a crest at the rear of the head

  • Pale underwings with dark patch in primaries

Adult alternate:

  • Deep red bill, often with indistinct black ring at tip

  • Black legs

  • Black cap with very slight crested appearance

  • White face, neck, breast, and belly

  • Pale gray back and upperwings

  • Pale underwings with dusky gray on outer 5-6 primaries

  • White tail

  • Takes three years to reach full adult plumage

Adult basic:

  • Similar to adult alternate, but has a black cap streaked with white and     darker, more worn, primaries

Juvenile:

  • Pale legs

  • Deep orange bill

  • Brownish cap streaked with white

  • Upperwing coverts and scapulars marked by crisp, black scalloping

  • White face, neck, breast, and belly

  • Pale upperwing has darker outer primaries and secondaries

  • Grayish tail

Immature:

  • 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

  • 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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