Ring-billed GullLarus delawarensis出会える場所と時期

The Ring-billed Gull is a medium-sized North American gull that readily uses inland waters. An adult’s dark bill band is memorable, but young birds are much less tidy-looking. The registered Columbia reach is Umatilla refuge and the John Day pool between Boardman and Irrigon. Species reference: https://www.allaboutbirds.org/guide/Ring-billed_Gull/id Measurements: https://en.wikipedia.org/wiki/Ring_billed_gull

サイズ

43–54 cm (17–21 in) long.

体重

300–700 g (11–25 oz).

寿命

Species-specific lifespan not verified.

ステータス

A current formal global assessment was not verified.

Birds forage while walking, swimming or flying and can assemble in mixed gull groups. Their adaptability makes them familiar around human activity, but an approachable gull is not necessarily tame. Do not feed birds from a vessel or encourage them to follow it; natural behaviour offers better identification evidence.

• Adults have yellow legs.
• The black bill band gives the species its name.
• Juveniles are mottled rather than clean grey and white.
• It regularly uses inland waters.
• The adult eye is pale.
• Umatilla includes John Day pool wetlands.

The retrieved eBird list includes dated observations, not a recurring local month matrix. Refuge-wide comments about seasonal waterfowl cannot be applied to gulls. Months remain empty. A May sighting is evidence of that encounter alone, not proof that May is the preferred annual viewing month.

Lakes, rivers and shores are part of its wider habitat use. At Umatilla, the refuge includes sloughs and wetlands influenced by the John Day pool, as well as riparian vegetation. That local setting supports the association without implying equal use of every reservoir bay or boat landing.

The species has an opportunistic diet including small animals and scavenged food. A detailed Columbia-specific dietary study was not verified. Avoid reducing its ecology to discarded human food merely because gulls may visit developed places. Feeding or scavenging observations should record what was actually visible, not an assumed menu.

一般的な名称

Ring-billed Gull

Scientific name

Larus delawarensis

動物グループ

Birds

サイズ

43–54 cm (17–21 in) long.

体重

300–700 g (11–25 oz).

寿命

Species-specific lifespan not verified.

ステータス

A current formal global assessment was not verified.

識別方法

Adults have a pale grey back, white body, yellow legs and a yellow bill crossed by a black band. The pale eye is useful at close range. Juveniles are mottled brown and white with a different bill appearance. A dark bill mark alone is not diagnostic across all ages and similar gull species.