[order] CHARADRIIFORMES | [family] Laridae | [latin] Larus thayeri | [UK] Thayers Gull | [FR] Goeland de Thayer | [DE] Thayermove | [ES] Gaviota esquimal | [NL]
Subspecies
Monotypic species
Physical charateristics
Very similar in appearance to Herring Gull. Typical adult has pale todark brown (not pale yellow) eyes, little or no black
on underside of primaries, slightly darker mantle, darker pink legs, slighter bill. Overhead, the gray (not black) on the underside of the wing tips is distinctive. Some paler birds may have slate gray rather than black in
the outer primaries above.
on underside of primaries, slightly darker mantle, darker pink legs, slighter bill. Overhead, the gray (not black) on the underside of the wing tips is distinctive. Some paler birds may have slate gray rather than black in
the outer primaries above.
Listen to the sound of Thayers Gull
[audio:http://www.aviflevoland.nl/sounddb/T/Thayers Gull.mp3]
Copyright remark: Most sounds derived from xeno-canto
| wingspan min.: | 130 | cm | wingspan max.: | 140 | cm |
| size min.: | 52 | cm | size max.: | 60 | cm |
| incubation min.: | 25 | days | incubation max.: | 28 | days |
| fledging min.: | 65 | days | fledging max.: | 75 | days |
| broods: | 1 | eggs min.: | 1 | ||
| eggs max.: | 4 |
Range
North America : North
Habitat
Coastal waters, bays.
Winters mostly in coastal regions, especially around estuaries and protected bays, also well offshore at times. May regularly visit freshwater ponds and garbage dumps in coastal plain. Rare in winter farther inland around lakes, rivers. Nests on rocky coa
sts of northern islands.
Winters mostly in coastal regions, especially around estuaries and protected bays, also well offshore at times. May regularly visit freshwater ponds and garbage dumps in coastal plain. Rare in winter farther inland around lakes, rivers. Nests on rocky coa
sts of northern islands.
Reproduction
Breeding behavior not well known, but probably somewhat similar to that of Herring Gull. Probably does not breed until 4 years old. Nests in colonies, sometimes in association with other species of gulls or other birds.
Nest: Site is on ledge of rocky cliff close to ocean, usually facing fjord or sound on Arctic island. Nest (probably built by both sexes) is a low mound of plant material with a hollowed-out depression at the center.
Eggs: 2, sometimes 3. Buff to olive or gray, with darker brown blotches. Incubation probably by both sexes; incubation period not known.
Young: Both parents probably feed young. Age of young at fledging and at independence not known.
Nest: Site is on ledge of rocky cliff close to ocean, usually facing fjord or sound on Arctic island. Nest (probably built by both sexes) is a low mound of plant material with a hollowed-out depression at the center.
Eggs: 2, sometimes 3. Buff to olive or gray, with darker brown blotches. Incubation probably by both sexes; incubation period not known.
Young: Both parents probably feed young. Age of young at fledging and at independence not known.
Feeding habits
Omnivorous.
Diet includes many small fish, also carrion, mollusks, crustaceans, berries. Around colonies of smaller seabirds, may take eggs or young. Also may feed on refuse around garbage dumps, docks, fishing boats.
Behavior: Forages in flight by dipping to surface of water to pick up items or by plunging to just below surface; also feeds while swimming or walking.
Diet includes many small fish, also carrion, mollusks, crustaceans, berries. Around colonies of smaller seabirds, may take eggs or young. Also may feed on refuse around garbage dumps, docks, fishing boats.
Behavior: Forages in flight by dipping to surface of water to pick up items or by plunging to just below surface; also feeds while swimming or walking.
Conservation
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size may be moderately small to large, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Migration
Arctic Canada. Winters mainly on Pacific coast. Migration: Most birds from central Canadian Arctic move so
uthwest to Pacific coast. Rare farther east in winter. Young birds tend to move farther south than adults; most found in southern California and northwestern Mexico are first-winter immatures.
uthwest to Pacific coast. Rare farther east in winter. Young birds tend to move farther south than adults; most found in southern California and northwestern Mexico are first-winter immatures.
Distribution map
