ringbilled gull (Larus delawarensis)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CONFIRMATION STATUS: Confirmed.

 

IDENTIFICATION:

  • Length: 16 inches Wingspan: 49 inches

  • Medium-sized gull

  • Fairly short, small bill with indistinct gonydeal angle

Adult alternate:

  • Bright yellow bill with complete black ring at gonys

  • Bright yellow legs

  • Yellow eye

  • White head, neck, breast and belly

  • Pale gray back and upperwings

  • White tertial crescent

  • Black primaries with white tips and two white mirrors on outer            primaries

  • White tail

Adult basic:

  • Like adult alternate but thin dark streaks about head and duller soft             parts

Juvenile:

  • Black bill quickly developing pale base

  • Pale head, breast, back and belly with light brown scalloping

  • Dark upperwing coverts with wide white edgings

  • Pale belly

  • Dark outer primaries

  • Dark terminal band on white tail

First-year:

  • Pink bill with black tip

  • Pink or gray legs

  • White head, neck and upper breast streaked with brown

  • Pale gray back

  • Upperwing coverts dull brown

  • Pale gray secondaries

  • Black primaries

  • Dark terminal band on white tail

Second-year:

  • Like adult basic but often with black-tipped yellow bill, entirely                  dark primaries and partial tail band

Similar species:

Adult herring gulls are similar to ring-billed gulls but are much larger,
have pinkish legs, and a much thicker yellow bill with more pronounc-

ed gonys. First-winter herring gulls are much browner, but second and
third-winter birds can be confusing since soft part colors are variable
and third-year herring gull often show a ring around the bill. Such
birds are most easily distinguished by the larger size and larger bill of
herring gull. California gulls are more similar in size and shape but are
still larger and bigger-billed. Adults are darker-backed than ringbill-

eds, with a brown eye, heavier head streaking, and a different bill pat-

tern. Immatures are browner overall and show less contrast between

the upperwing coverts and the secondaries. Adult mew gulls have un-

marked bills, a darker gray back and are smaller. Juvenile mew gulls are

much darker. First and second-winter mew gulls have a darker gray back

and a daintier appearance. Common black-headed and Bonaparte's gulls

are somewhat smaller in winter but have dark auriculars and very different

wing markings in flight. Winter adult black-legged kittiwake has a plain

yellow bill and entirely black wingtips.

 

LIFE HISTORY

Migration Status: N/A
Breeding Habitat: Wetland-open water
Nest Location: N/A
Nest Type: N/A
Clutch Size: 3
Length of Incubation: 21 days
Days to Fledge: ?
Number of Broods: 1
Diet: Primarily fish, insects, aquatic invertebrates; lesser quantities of
   carrion, plant matter

 

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
U
      Su - Summer: June, July, August Acc
      Fall: September, October, November

      Winter: December, January, February U

 

 

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