Overview

Distribution

occurs (regularly, as a native taxon) in multiple nations

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

National Distribution

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Breeding

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Global Range: BREEDS: interior North America from southern Mackenzie, Saskatchewan, and Manitoba south to east-central North Dakota, central Montana, northwestern Wyoming, eastern Idaho, northwestern Utah, northwestern Nevada, eastern California, southeasternuthern Washington. The largest nesting concentration (about 130,000-150,000 in 1988-1991) occurs around the Great Salt Lake, Utah (Paton et al. 1992). WINTERS: southern Washington, eastern Idaho, south along Pacific coast to southern Baja California northwestern Mexico; rare in Hawaii.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Range Description

The breeding range of this species in in western North America from Northwest Territories (Canada) south to eastern California and Colorado (USA). It winters in coastal regions from south-west Canada to south-west Mexico1.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Geographic Range

California gulls are North American birds. They are found in regions of Mexico, the west coast of the United States, the Great Plains, and western Canada. The species has been reported to live in California, Colorado, Kansas, Nevada, North Dakota, Oregon, Texas, Utah, Washington, and Wyoming. The birds are found in different regions depending on the season. In the summer, during breeding season, they are found in parts of northwestern Wyoming, northern Utah, western Nevada, and northern California. During the winter, California gulls can be observed on the Pacific coast from southern British Columbia to southern Mexico. The gulls migrate to North Dakota, British Columbia, lower California, and Monterey, California during the spring. In the fall the gulls migrate southwest to the coast in the states of Washington, Oregon, and California.

Biogeographic Regions: nearctic (Native )

  • Bent, A. 1939. Life Histories of North American Gulls and Terns. Washington, D.C.: Washington Government Printing Office.
  • Winkler, D. 1996. California gull : Larus californicus. The Birds of North America, 259: 1-27.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Physical Description

Morphology

Physical Description

The average California gull is around 54 cm long and weighs about 600 g. While there are no differences in male and female plumage, males are usually larger than females, with a larger bill, head, and tarsi. When the bird is newly born it has a thick, soft down of light colors that blend in with the surrounding environment. By the juvenile's first winter, it has a brown mantle and wings, a brown head, and pink tinted legs. When the bird is around two years old the tail becomes white and the bill turns yellow. When the gull reaches its third year, it almost is completely like the adult in appearance, but the adult bill pattern and wing pattern are not completely developed. By the fourth winter the bird has an adult's white head, dark grey mantle, yellow green legs, reddish eye ring, and black wingtips.

Range mass: 432 to 885 g.

Average mass: 600 g.

Range length: 51 to 58 cm.

Average length: 54 cm.

Sexual Dimorphism: sexes alike; male larger

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Size

Length: 53 cm

Weight: 609 grams

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Ecology

Habitat

Comments: Seacoasts, bays, estuaries, mudflats, marshes, irrigated fields, lakes, ponds, dumps, cities, and agricultural lands (AOU 1983). Nests inland on open sandy or gravelly areas on islands or along shores of lakes and ponds, generally with scattered grasses. Nests on ground. Prefers fairly open area with irregular terrain near shore of islands (Jehl and Mahoney 1987). NON-BREEDING: In autumn migration, the most abundant gull in pelagic waters off the British Columbia and Washington coast (Campbell 1990).

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Habitat and Ecology

Habitat and Ecology
This species can be found on a variety of habitats, including coasts, estuaries, bays, mudflats and fields, breeding in open habitats usually on low rocky islands in freshwater and hypersaline lakes. Its breeding season begins in early May, laying in April and May in colonies. It feeds on insects, grubs, the eggs and young of birds, rodents, rubbish, grain and berries (del Hoyo et al. 1996).

Systems
  • Terrestrial
  • Freshwater
  • Marine
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

California gulls live in areas that contain lakes, marshes, and along the seacoast. They also reside on offshore islands, near rivers, agricultural land, and garbage dumps. When breeding, they often construct their nests near shrubs by bodies of water.

Habitat Regions: temperate ; terrestrial

Aquatic Biomes: lakes and ponds; rivers and streams; coastal

Wetlands: marsh

Other Habitat Features: urban ; agricultural ; riparian

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Depth range based on 11544 specimens in 1 taxon.
Water temperature and chemistry ranges based on 2901 samples.

Environmental ranges
  Depth range (m): 0 - 0
  Temperature range (°C): 10.712 - 17.265
  Nitrate (umol/L): 0.038 - 4.675
  Salinity (PPS): 30.381 - 33.501
  Oxygen (ml/l): 5.540 - 6.587
  Phosphate (umol/l): 0.330 - 0.800
  Silicate (umol/l): 1.436 - 16.169

Graphical representation

Temperature range (°C): 10.712 - 17.265

Nitrate (umol/L): 0.038 - 4.675

Salinity (PPS): 30.381 - 33.501

Oxygen (ml/l): 5.540 - 6.587

Phosphate (umol/l): 0.330 - 0.800

Silicate (umol/l): 1.436 - 16.169
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Migration

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Trophic Strategy

Comments: In inland areas, feeds on insects (crickets, grasshoppers, cutworms) and mice. At Mono Lake, California, recently fledged gulls fed mainly on, and aparently preferred, alkali flies (Elphick and Rubega 1995, Great Basin Nat. 55:363-367). Along the coast, feeds on dead fish and garbage; scavenges behind boats, around harbors and dumps.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Food Habits

Food preferences vary with the location of the bird's habitat. Favorite foods of California gulls include fish, birds, small mammals such as gophers and mice, garbage, insects, and aquatic invertebrates.

The birds use a range of different techniques to capture food. They often retrieve food such as fish near the surface of the water or brine shrimp by diving and pecking. The gulls capture small mammals like mice that have been flooded out of their holes by irrigation. In some instances the birds steal the eggs and chicks of other gulls in the colony. California gulls eat plant foods such as grains, vegetables, and especially cherries. The birds knock the cherries off the trees and then pick them up off the ground. They can also be found at garbage dumps dining on scraps of trash.

Animal Foods: birds; mammals; fish; eggs; insects; aquatic crustaceans

Plant Foods: seeds, grains, and nuts; fruit

Primary Diet: omnivore

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Associations

Ecosystem Roles

California gulls have an impact on the prey they consume.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Predation

When a bird predator such as an eagle approaches the colony, the gulls respond with alarm and warning calls. When a coyote enters the colony, gulls may dive at it and sound warning calls. If a human comes into a gull colony the response will be even more severe. It is not uncommon for California gulls to attack humans by plunging at them.

Young gulls have cryptic coloration that helps to protect them from predators.

Known predators include: great horned owl (Bubo virginianus), golden eagle (Aquila chrysaetos), bald eagle (Haliaeetus leucocephalus), prairie falcon (Falco mexicanus), red-tailed hawk (Buteo jamaicensis), herring gull (Larus argentatus), red fox (Vulpes vulpes), weasel (family Mustelidae), feral dog (Canis lupus familiaris), muskrat (family Muridae), gopher snake (Pituophis melanoleucus), northern pike (Esox lucius), Canada goose (Branta canadensis), raccoon (Procyon lotor), skunk (family Mustelidae), river otter (Lontra canadensis) and other California gulls.

Known Predators:

Anti-predator Adaptations: cryptic

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Known predators

Creative Commons Attribution 3.0 (CC BY 3.0)

© SPIRE project

Source: SPIRE

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Known prey organisms

Larus californicus preys on:
non-insect arthropods
Actinopterygii
Crustacea
Insecta
Aves
Mammalia
Anas americana
Aythya americana

This list may not be complete but is based on published studies.
Creative Commons Attribution 3.0 (CC BY 3.0)

© SPIRE project

Source: SPIRE

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

General Ecology

May gather in large flocks, often in association with Herring and Ring-billed Gulls. Great Horned Owl may cause significant mortality in breeding colony (California, Jehl and Mahoney 1987). Home range: breeding pairs in Montana foraged an average of 17.4 kilometers (maximum 61 kilometers) from colony (Baird 1976). At another colony, maximum foraging distance was 32 kilometers (Rothweiler 1960).

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Life History and Behavior

Behavior

Communication and Perception

Vocalized sounds serve as the main form of communication for California gulls. Young chicks use begging calls to let the parents know when they are hungry. As the birds get older the sounds increase in volume. When a predator enters the colony the gulls issue a warning call by dropping the pitch of the sound and stressing the second syllable. The mew call is a series of soft low notes used during courtship, courtship feeding, and copulation. When a mate returns to the nest to exchange duties with its partner, the mew call is also used. Furthermore, the mew sound is used in territorial conflicts. When the female gull wants her mate to feed her, the begging call is used. The copulation call is used solely by the male during copulation. California gulls use an alarm call of several sharp notes in response to the threat of a predator. When chasing or attacking a predator, the birds sound the charge call. If a bird is captured and struggling to escape, it emits the shrill waver, a hoarse thin call. (Bent, 1939; Winkler, 1996)

Members of this species also communicate through their posture. If a gull feels threatened, it holds its wings slightly away from its body. As a California gull prepares to attack, it gets into the lunge position. Pulling grass from the ground is another threat to other animals. Fights between individuals usually occur between two birds of the same sex. These physical demonstrations are often used along with calls. (Winkler, 1996)

Communication Channels: visual ; acoustic

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Life Cycle

Development

The young birds leave the territory of their parents forty to sixty days after they are born. By this time they are almost fully grown; however, feathers are still developing. The birds usually achieve their adult plumage and reach sexual maturity after four years. After leaving the parental colony, fledglings gather at the edge of water and swim together, usually forming groups at areas where substantial food is available. The ability of the birds to fly and feed improves to an adult level after around a month after they have left the territory of their parents.(Hobert, 2000; Winkler, 1996)

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Life Expectancy

Lifespan/Longevity

The lifespan of California gulls is usually between 4 and 24 years (20 on average). The oldest known California gull reached 30 years. Causes of death include exposure to cold weather, predation, parasitism, and competition with other species.

Range lifespan

Status: wild:
30 (high) years.

Typical lifespan

Status: wild:
4 to 24 years.

Average lifespan

Status: wild:
20 years.

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Lifespan, longevity, and ageing

Maximum longevity: 30 years (wild)
Creative Commons Attribution 3.0 (CC BY 3.0)

© Joao Pedro de Magalhaes

Source: AnAge

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Reproduction

Breeding begins late April in south to early June in north. Both sexes incubate 3 eggs for 23-27 days. Semi-precocial young are tended by both parents. In southern California, fledging was almost complete by the end of July. May form female-female pairs.

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

The "Head-Tossing Display" and the "Begging Call" are used to prompt copulation or courtship-feeding in California gulls. The ritual of courtship-feeding where the male bird delivers food to the female may occur during the pre-egg laying and early egg-laying stages. The "Head-Tossing Display" and "Begging Calls" can be used by either males or females to iniciate copulation. During copulation the male jumps onto the female's back and gives the "Copulation Call". Pairs usually remain together each breeding season, but in some cases partners change.

Mating System: monogamous

California gulls return to their home colony each year about three to seven weeks before they begin to lay their eggs. The breeding season occurs from May to July. Once a pair has formed, and the nest has been in the process of construction for around a week, egg laying begins. The birds lay one egg every other day until they have laid between two to five eggs. The eggs hatch after about 24 days and the chicks fledge within 40 to 60 days. A second brood is laid only if the first was unsuccessful. The birds usually build their nests close to shrubs by water sources such as marshes, ocean coasts, or lakes. Young birds reach sexual maturity after 4 years.

Breeding interval: California gulls breed once yearly

Breeding season: May to July

Range eggs per season: 2 to 5.

Average eggs per season: 3.

Range time to hatching: 23 to 26 days.

Average time to hatching: 24 days.

Range fledging age: 40 to 60 days.

Range age at sexual or reproductive maturity (female): 4 to 4 years.

Range age at sexual or reproductive maturity (male): 4 to 4 years.

Key Reproductive Features: seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization (Internal )

Average eggs per season: 3.

The male and female take turns incubating; the nonincubating parent guards the nest and hunts for food. In rare cases the chick will be smothered by the parent while it is trying to hatch because the parent is sitting too securely on the egg. Both parents feed the precocial offspring until they fledge. The parents swallow food, take it back to the nest, and regurgitate it in order to feed it to their young.

Parental Investment: no parental involvement; precocial ; pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female)

  • Bent, A. 1939. Life Histories of North American Gulls and Terns. Washington, D.C.: Washington Government Printing Office.
  • Winkler, D. 1996. California gull : Larus californicus. The Birds of North America, 259: 1-27.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Molecular Biology and Genetics

Molecular Biology

Barcode data: Larus californicus

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 6 barcode sequences available from BOLD and GenBank.

Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.

See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

CCTATACTTAATCTTTGGCGCATGAGCTGGCATAGTAGGTACTGCCCTCAGCCTGCTTATCCGCGCAGAACTTGGCCAACCCGGAACCCTCCTAGGAGACGACCAAATCTATAACGTAATTGTCACCGCCCATGCCTTCGTGATAATCTTCTTCATAGTGATACCAATCATGATCGGTGGGTTTGGAAACTGACTAGTCCCACTTATAATCGGTGCCCCTGATATAGCATTTCCACGCATAAACAACATAAGCTTCTGACTATTACCCCCATCATTCCTACTCCTCCTAGCCTCTTCCACAGTAGAAGCTGGAGCCGGCACAGGATGAACAGTATACCCCCCTCTAGCTGGCAATCTAGCCCATGCTGGAGCCTCAGTAGACCTAGCAATCTTCTCTCTTCACTTAGCAGGTGTGTCTTCCATTCTGGGTGCTATCAACTTTATCACTACAGCCATCAACATAAAACCCCCTGCCCTCTCACAATATCAAACCCCACTATTCGTATGATCCGTACTCATCACTGCCGTCCTATTACTACTTTCACTCCCAGTGCTTGCCGCAGGCATTACTATGCTACTTACAGACCGAAACCTAAACACAACATTCTTCGATCCCGCCGGAGGCGGTGACCCTGTACTGTACCAACACCTCNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
-- end --

Download FASTA File

Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Statistics of barcoding coverage: Larus californicus

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 6
Specimens with Barcodes: 8
Species With Barcodes: 1
Creative Commons Attribution 3.0 (CC BY 3.0)

© Barcode of Life Data Systems

Source: Barcode of Life Data Systems (BOLD)

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Conservation

Conservation Status

National NatureServe Conservation Status

Canada

Rounded National Status Rank: N5B - Secure

United States

Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

NatureServe Conservation Status

Rounded Global Status Rank: G5 - Secure

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

IUCN Red List Assessment


Red List Category
LC
Least Concern

Red List Criteria

Version
3.1

Year Assessed
2012

Assessor/s
BirdLife International

Reviewer/s
Butchart, S. & Symes, A.

Contributor/s

Justification
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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not 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.
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

The world-wide population of California gulls is somewhere between 500,000 and 1 million birds and growing. The gulls are not often killed by humans because they are usually appreciated for their benefits to agriculture. Occasionally gulls are killed by six-pack drink carriers which get caught around the gulls' necks when they feed on trash from garbage dumps. This can easily be prevented by cutting up the plastic before throwing it away.

California gulls are protected under the Migratory Bird Treaty Act, but are not listed by the IUCN, the US Federal List or CITES.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Population

Population Trend
Decreasing
Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© International Union for Conservation of Nature and Natural Resources

Source: IUCN

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Relevance to Humans and Ecosystems

Benefits

Economic Importance for Humans: Negative

While California gulls help farmers more often then not, recently they have caused problems by ravaging cherry crops. The birds beat the cherries off the trees and then collect and eat the fallen fruit from the ground.

Negative Impacts: crop pest

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Economic Importance for Humans: Positive

California gulls are famous for reputedly aiding settlers in Salt Lake City, Utah, by eating the "locusts" (probably Mormon crickets, Anabrus simplex) that threatened their crops. California gulls benefit agriculturalists economically because they feed on the pests that destroy their crops, such as mice, and insects. Mouse holes often ruin crops, but as the fields are irrigated, mice are forced to come out of their holes and they are then eaten by the birds. Also, California gulls pick up trash along the edges of rivers and lakes, helping to keep areas free from garbage.

Positive Impacts: controls pest population

Creative Commons Attribution Non Commercial Share Alike 3.0 (CC BY-NC-SA 3.0)

© The Regents of the University of Michigan and its licensors

Source: Animal Diversity Web

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Wikipedia

California gull

In California

The California gull (Larus californicus) is a medium-sized gull, smaller on average than the herring gull but larger on average than the ring-billed gull, though may overlap in size greatly with both.

Adults are similar in appearance to the herring gull, but have a smaller yellow bill with a black ring, yellow legs, brown eyes and a more rounded head. The body is mainly white with grey back and upper wings. They have black primaries with white tips. Immature birds are also similar in appearance to immature herring gulls, with browner plumage than immature ring-billed gulls. Length can range from 46 to 55 cm (18 to 22 in), the wingspan 122–137 cm (48–54 in) and body mass can vary from 430 to 1,045 g (0.948 to 2.304 lb).[2]

Winter plumage, California

Their breeding habitat is lakes and marshes in interior western North America from Northwest Territories, Canada south to eastern California and Colorado.[3] They nest in colonies, sometimes with other birds. The nest is a shallow depression on the ground lined with vegetation and feathers. The female usually lays 2 or 3 eggs. Both parents feed the young birds.

They are migratory, most moving to the Pacific coast in winter. It is only then that this bird is regularly found in western California.[3]

These birds forage in flight or pick up objects while swimming, walking or wading. They mainly eat insects, fish and eggs. They also scavenge at garbage dumps or docks. They may follow plows in fields for insects stirred up by this activity.

This is the state bird of Utah,[4] remembered for assisting Mormon settlers in dealing with a plague of Mormon crickets.[5] A monument in Salt Lake City commemorates this event, known as the "Miracle of the Gulls".[5]

There are two subspecies recognized, the nominate from the Great Basin to central Montana and Wyoming, and the slightly larger, paler L. c. albertaensis with a more northerly distribution, ranging from Great Slave Lake onto the Great Plains of western Manitoba and South Dakota.[6] Although these subspecies are not well distinguishable by mtDNA allozyme variation,[7] they breed true and the low genetic divergence can be explained by separation during the Pleistocene and renewed contact in Montana during more recent times.[8]

Hand-painted glass slide of a colony of California gulls at Malheur Lake, taken by Finley and Bohlman during a 1908 photograph trip to the area. Finley and Bohlman's photographs would later help Malheur become a bird refuge in 1908.

In California, the California gull recently held the protected status California Species of Special Concern due to declining numbers at their historic California breeding colony at Mono Lake. However, in recent decades this species has begun to breed in the southern portion of San Francisco Bay, where it did not historically breed, and has undergone exponential population growth. These California gulls now inhabit large, remote salt-production ponds and levees and have a very large food source provided by nearby landfills from San Francisco, San Jose and other urban areas, all the way up into the Sacramento area. The South Bay California Gull population has grown from less than 1,000 breeding birds in 1982 to over 33,000 in 2006. This population boom has resulted in large resident flocks of gulls that will opportunistically prey on other species, particularly the eggs and nestlings of other birds. Seriously threatened birds that share the same South Bay habitat include the snowy plover and California least tern, while less-threatened birds including black-necked stilts, American avocets, Forster's terns, and Caspian terns are also preyed upon by the abnormally large flocks of California gulls. Efforts are underway to reduce habitat for this species and find other ways to disperse the large numbers of gulls.[9]

References[edit]

  1. ^ BirdLife International (2012). "Larus californicus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013. 
  2. ^ CRC Handbook of Avian Body Masses by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0-8493-4258-5.
  3. ^ a b Sibley, David Allen (2000): The Sibley Guide to Birds. Alfred A. Knopf, New York. ISBN 0-679-45122-6
  4. ^ "Utah State Bird". Utah.gov. Retrieved 11 August 2014. 
  5. ^ a b Ryser, Fred A. (1985). Birds of the Great Basin. Reno, NV, USA: University of Nevada Press. p. 203. ISBN 0-87417-080-X. Retrieved 11 August 2014. 
  6. ^ Jehl, Joseph R., Jr. (1987). "Geographic variation and evolution in the California Gull (Larus californicus)". Auk 104 (3): 421–428. doi:10.2307/4087540. 
  7. ^ Karl, S. A.; Zink, R. M.; Jehl, Joseph R. Jr. (1987). "Allozyme analysis of the California Gull (Larus californicus)". Auk 104 (4): 767–769. 
  8. ^ Jehl, Joseph R., Jr.; Francine, J; Bond, S. I. (1990). "Growth patterns of two races of California Gulls raised in a common environment". Condor 92 (3): 732–738. doi:10.2307/1368692. 
  9. ^ Ackerman, J. T., J. Y. Takekawa, C. Strong, N. Athearn, and A. Rex. (2006) California Gull distribution, abundance, and predation on waterbird eggs and chicks in South San Francisco Bay. Final Report, U. S. Geological Survey, Western Ecological and Research Center, Davis and Vallejo, CA.
Creative Commons Attribution Share Alike 3.0 (CC BY-SA 3.0)

Source: Wikipedia

Unreviewed

Article rating from 0 people

Default rating: 2.5 of 5

Names and Taxonomy

Taxonomy

Comments: Closely interrelated with L. argentatus, L. cachinnans, L. thayeri, L. glaucoides, and L. fuscus (AOU 1998).

Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© NatureServe

Source: NatureServe

Trusted

Article rating from 0 people

Default rating: 2.5 of 5

Disclaimer

EOL content is automatically assembled from many different content providers. As a result, from time to time you may find pages on EOL that are confusing.

To request an improvement, please leave a comment on the page. Thank you!