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Larus californicus

(California Gull)

Overview:

This versatile bird is capable of feeding on foot, on the wing, while swimming, or by diving. Large species of gulls are important hunters of the treeless Arctic plains, feeding on small mammals and birds, chicks, and eggs.

Conservation Status

Population Analysis

  • For the 56,576 species in the Class Aves (Birds), we average 371.87 observations each in our database; for the California Gull, we have 14,335 observations. Compared to other species in this Class, this species is moderately common.
  • A two-sample t-test can be used to determine whether the trend in observations of the California Gull is the same as the trend in observations of Aves. Is this species just as common, as a proportion of all observations, as it once was? The answer is no, changes in observation rate of this species significantly differ from changes in observation rate of its Class. (t=35.57, p<0.001)
  • How do observation rates of the California Gull differ from those of Aves? To answer this, we examined the percentage of observerations for Aves that were observations of the California Gull each year. We then correlated this percentage with observation year. If observations of the California Gull are becoming more common relative to other species of Aves, the correlation should be positive, but if it is becoming less common, the correlation should be negative. In fact, the correlation is negative (r=-.08), with a negative slope (m = -.002), suggesting that the California Gull may be in decline relative to other species of Aves. This correlation is statistically significant. (F = 12.95, p<.05)
  • The scatter chart to the right shows the percentage of all observations for Aves each year that were observations of the California Gull.

History:

  • 1988-Lower Risk/least concern (BirdLife International 2004)
  • 1994-Lower Risk/least concern (BirdLife International 2004)
  • 2000-Lower Risk/least concern (BirdLife International 2000)

Justification

This species has a large range, with an estimated global extent of occurrence of 2,000,000 km². It has a large global population estimated to be 620,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern.

Taxonomy

  • Domain: Eukaryota Whittaker & Margulis,1978 - eukaryotes
    • Kingdom: Animalia Linnaeus, 1758 - Linnaeus, 1758 - animals
      • Subkingdom: Bilateria (Hatschek, 1888) Cavalier-Smith, 1983 - (Hatschek, 1888) Cavalier-Smith, 1983 - bilaterians

Notes:

Name Status: Accepted Name. Latest taxonomic scrutiny: 17-Oct-2001

Physical Description

Family Laridae:

Medium to large birds, usually grey or white, often with black markings on the head or wings. They have stout, longish bills, and webbed feet.

Adult:

Head: white Bill: yellow with red and yellow spot on lower mandible Lower Mandible: red and black spot Neck: white Body: Breast: white Underparts: white Legs: Foot Color: greenish-yellow to gray-green Leg Color: greenish-yellow to gray-green Tail: white.

Size/Age/Growth:

About 21 to 22 inches long, with a wingspan of 48 to 54 inches. Adults weigh about 22.4 ounces.

Images:

Distribution

Range and Population

Oceania; North America

Habitat

Vegetation: freshwater marshes, coastal waters, coastal sand beaches and mudflats, arid lowland scrubs, pastures and agricultural lands, freshwater lakes and ponds • Minimum Elevation: 0 meters • Maximum Elevation: 1,600 meters • Sensitivity to Disturbance: Low.

Diet

Mostly: Insects Aquatic Invertebrates Fish Carrion

Reproduction

  • Breeding Habitat: Wetland-open water
  • Clutch Size: 1-3
  • Length of Incubation: 25(23-27) days
  • Days to Fledge: 45
  • Number of Broods: 1

Migration

Migratory

Song/Voice


Larus californicus
Recordist: Doug Von Gausig Date Recorded: March 15, 1999 Location of Recording: Monterey, CA Copyright Holder: NatureSongs.com Permissions for Use: Read this

Similar Species

Ring-Billed Gull, Herring Gull

Members of the genus Larus:

There are approximately 188 species and subspecies in this genus. Here are just 100 of them: L. africilla (Laughing Gull) · L. argentatus (Herring Gull) · L. argentatus antelius · L. argentatus argentatus (Herring Gull) · L. argentatus argenteus · L. argentatus atlantis · L. argentatus birulae · L. argentatus cachinnans · L. argentatus drosti · L. argentatus heuglini · L. argentatus hueglini · L. argentatus michahelis · L. argentatus michahelles · L. argentatus michahellis · L. argentatus mongolicus · L. argentatus omissus · L. argentatus smithsonianus · L. argentatus ssp · L. argentatus thayeri · L. argentatus vegae · L. armenicus (Armenian Gull) · L. atlanticus (Olrog's Gull) · L. atricilla (Laughing Gull) · L. atricilla atricilla · L. atricilla megalopterus · L. audouinii (Audouin's Gull) · L. belcheri (Band-Tailed Gull) · L. belcheri atlanticus · L. belcheri belcheri · L. borealis · L. brachyrhynchus · L. brachyrhynchus (Red-Legged Kittiwake) · L. bridgesii · L. brunneicephalus · L. brunnicephalus (Brown-Headed Gull) · L. bulleri (Black-Billed Gull) · L. byperboreus · L. cachin · L. cachinnans (Yellow-Legged Gull) · L. cachinnans atlantis · L. cachinnans barabensis · L. cachinnans cachinanns · L. cachinnans cachinnans · L. cachinnans michahellis · L. cachinnans mongolicus · L. californicus (California Gull) · L. californicus albertaensis · L. californicus californicus · L. californicus ssp · L. canus (Mew Gull) · L. canus brachyrhynchus (Mew Gull) · L. canus canus (Mew Gull) · L. canus heinei (Mew Gull) · L. canus kamtschatschensis · L. capistratus · L. cirrhocephalus · L. cirrhocephalus cirrhocephalus · L. cirrocephalus (Grey-Headed Gull) · L. cirrocephalus cirrocephalus · L. cirrocephalus poiocephalus · L. crassirostris (Black-Tailed Gull) · L. delawarenis · L. delawarensis (Ring-Billed Gull) · L. delewarensis · L. dominicanus (Kelp Gull) · L. dominicanus austrinus · L. dominicanus dominicanus · L. dominicanus melisandae · L. dominicanus vetula · L. dominicanus vetula (Ivory Gull) · L. eburneus · L. elegans · L. franklerii · L. fuliginosus (Lava Gull) · L. furcatus (Swallow-Tailed Gull) · L. fuscus (Lesser Black-Backed Gull) · L. fuscus antelius · L. fuscus britannicus · L. fuscus fuscus (Lesser Black-Backed Gull) · L. fuscus graellsi · L. fuscus graellsii (Lesser Black-Backed Gull) · L. fuscus heuglini · L. fuscus intermedius · L. gelastes · L. genei (Slender-Billed Gull) · L. glaucescens (Glaucous-Winged Gull) · L. glaucescens californicus · L. glaucescens hybrid · L. glaucescens occidentalis · L. glaucescens x · L. glaucoides (Iceland Gull) · L. glaucoides glaucoides (Iceland Gull) · L. glaucoides kumlieni (Iceland Gull) · L. glaucoides thayeri (Iceland Gull) · L. glaucus · L. haematorhynchus · L. hartlaubi · L. hartlaubii (King Gull) · L. heermanni (Heermann's Gull) · L. heermanni heermanni

Bibliography

  • Alsop, Fred J. III. Birds of North America - Eastern Region. First American Edition. Smithsonian Handbooks. DK Publishing, Inc. 2001.
  • Banks, R. C., R. W. McDiarmid, A. L. Gardner, and W. C. Starnes 2003. Checklist of Vertebrates of the United States, the U.S. Territories, and Canada.
  • BirdLife International. 2000. Threatened Birds of the World. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, U.K.
  • Ehrlich, P., Dobkin, D., and Wheye, D. (1988). The Birders Handbook: A Field Guide to the Natural History of North American Birds. New York: Simon and Schuster Inc. (info on clutch size, length of incubation, days to fledge and number of broods.)
  • Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc. (Length and wingspan info.)

More Info

Notes

Contributors:

  • BirdLife International 2004. Larus californicus. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. www.iucnredlist.org . Downloaded on 21 October 2006.
  • Bisby, F.A., Y.R. Roskov, M.A. Ruggiero, T.M. Orrell, L.E. Paglinawan, P.W. Brewer, N. Bailly, J. van Hertum, eds (2007). Species 2000 & ITIS Catalogue of Life: 2007 Annual Checklist. Species 2000: Reading, U.K.
  • Brands, S.J. (comp.) 1989-2006. Systema Naturae 2000. The Taxonomicon. Universal Taxonomic Services, Amsterdam, The Netherlands. Accessed April 21, 2007.
  • Global Biodiversity Information Facility. Accessed March 04, 2008. http://www.gbif.org Mediated distribution data from 11 providers.
  • Hines, J. E., Gregory Gough, J. R. Sauer, et al. USGS Patuxent Wildlife Research Center
  • Parker III, T.A., D.F. Stotz, and J.W. Fitzpatrick, and quot;Ecological and Distributional Databases for Neotropical Birds, and quot; in Neotropical Birds: Ecology and Conservation, by D.F. Stotz, T.A. Parker III, J.W. Fitzpatrick, and D.K. Moskovits (Chicago: University of Chicago Press, 1996). ISBN 0-226-64676-9.
  • Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, Results and Analysis 1966 - 2004. Version 2005.2. USGS Patuxent Wildlife Research Center, Laurel, MD
  • Sauer, J. R., S. Schwartz, and B. Hoover. 1996. The Christmas Bird Count Home Page. Version 95.1. USGS Patuxent Wildlife Research Center, Laurel, MD
  • Smithsonian National Museum of Natural History

Data Sources:

Accessed through GBIF Data Portal March 04, 2008:

  • Avian Knowledge Network: eBird
  • Avian Knowledge Network: Great Backyard Bird Count
  • Avian Knowledge Network: Project FeederWatch
  • Bird Studies Canada: BC Coastal Waterbird Survey
  • Borror Laboratory of Bioacoustics
  • Canadian Biodiversity Information Facility: North West Territories and Nunavut Bird Checklist, Canada
  • Canadian Biodiversity Information Facility: Ontario Nest Records
  • Canadian Biodiversity Information Facility: Provincial Museum of Alberta, Edmonton, AB, Canada. Birds (Aves)
  • Canadian Biodiversity Information Facility: Royal British Columbia Museum
  • Canadian Museum of Nature: Canadian Museum of Nature Bird Collection
  • Institute of Marine and Coastal Sciences, Rutgers University: SEAMAP - marine mammals, birds and turtles
  • Museum of Vertebrate Zoology: Terrestrial vertebrate specimens
  • Santa Barbara Museum of Natural History: Santa Barbara Musem of Natural History
  • UCLA-Dickey Bird Collection (UCLA-Dickey): Bird specimens
  • UNIBIO, IBUNAM: CNAV/Coleccion Nacional de Aves
  • University of Michigan Museum of Zoology (UMMZ): Bird specimens

Identifiers:

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Last Revised: May 05, 2008