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Overview
Distribution
Range
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, B.L. Sullivan, C. L. Wood, and D. Roberson. 2012. The eBird/Clements checklist of birds of the world: Version 6.7. Downloaded from http://www.birds.cornell.edu/clementschecklist/downloadable-clements-checklist
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Range Description
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Geographic Range
The Pacific Loon is found along the Western Coast of the United States during the fall and winter, and in Northern Canada and Alaska where they migrate for the breeding months of the spring and summer.
Biogeographic Regions: nearctic (Native )
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National Distribution
Canada
Origin: Native
Regularity: Regularly occurring
Currently: Present
Confidence: Confident
Type of Residency: Year-round
United States
Origin: Native
Regularity: Regularly occurring
Currently: Present
Confidence: Confident
Type of Residency: Year-round
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Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) BREEDS: eastern Siberia from Arctic coast south to Anadyrland; Arctic coast of Alaska and Canada east to Baffin Island, south to southern Alaska, southwestern Yukon, northern Manitoba, and northwestern Quebec. WINTERS: south to Japan and along Pacific coast of North America south to Baja California and southern Sonora. In North America, areas of highest winter density include British Columbia around Vancouver Island, Monterey Bay in California, and near Point Whiteshed in Alaska (Root 1988). Casual/uncommon migrant inland in western U.S., very rare on east coast (NGS 1983).
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Physical Description
Morphology
Physical Description
The Pacific Loon's head is black which extends down the back of its neck and back where there are some mottled white spots. On its underside the color is white extending from its bill to its belly. Its average length is 66 cm.
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Size
Diagnostic Description
Arctica has more white on the flanks at the waterline than does G. PACIFICA (see McCaskie et al. 1990, Roberson 1989, and Schulenberg 1989 for further details).
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Ecology
Habitat
Habitat and Ecology
Systems
- Terrestrial
- Freshwater
- Marine
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Pacific Loons reside for the most part along the eastern coast of the Pacific Ocean and Arctic Ocean along Canada's northern boundary. They can also be found in inland waterways and even lakes occurring along their migratory paths. They are sensitive to disturbances, especially those created by humans, and are most likely to occur in remote areas. Their nest are found right along the shoreline and will be abandoned if receding waters cause the nest to be too far from the edge of the water. Recently loons have become a pest on lakes that are commercially stocked with fish.
Aquatic Biomes: lakes and ponds; coastal
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Water temperature and chemistry ranges based on 105 samples.
Environmental ranges
Depth range (m): 0 - 0
Temperature range (°C): 12.490 - 16.316
Nitrate (umol/L): 0.240 - 3.951
Salinity (PPS): 32.851 - 33.496
Oxygen (ml/l): 5.685 - 6.169
Phosphate (umol/l): 0.330 - 0.674
Silicate (umol/l): 1.436 - 6.162
Graphical representation
Temperature range (°C): 12.490 - 16.316
Nitrate (umol/L): 0.240 - 3.951
Salinity (PPS): 32.851 - 33.496
Oxygen (ml/l): 5.685 - 6.169
Phosphate (umol/l): 0.330 - 0.674
Silicate (umol/l): 1.436 - 6.162
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
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Comments: Nonbreeding: primarily seacoasts, bays and estuaries, less frequently on lakes and rivers (AOU 1983). In winter off central California, generally stays 2-8 km offshore (see Root 1988). In spring in southern California, migrants may be attracted to cool waters near the frontal boundaries of upwelling plumes, where loon prey is attracted by concentrations of zooplankton (Russell and Lehman 1994).
Nests on lakes/ponds in tundra or taiga. Usually nests on largest pond available (0.2-21 ha in one study area); selects ponds with islands or wet grassy areas. Nests on ground in scrape or on mound of material on ground in or very near water. Prefers to nest on island or at end of point extending into water (Johnson and Herter 1989).
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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.
Highly migratory (small flocks); some travel 12,000 miles/years (Oberholser 1974); others move only to coastal waters near breeding range. Main migration in California: November-early December, late April-May; in southern California, spring migration peaks sometimes between mid-April and early May (Russell and Lehman 1994). Arrives southeastern Alaska by early May, arctic coast early June (sometimes late May). Peak fall migration in arctic Alaska late August-September (Johnson and Herter 1989).
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Trophic Strategy
Food Habits
The Pacific Loon feeds mainly on small fish and other aquatic life. Fishing is conducted beneath the surface where they make good use of well-developed air sacs, which allow them to pursue their prey for extended periods.
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Comments: Feeds on fishes as well as crustaceans, mollusks, and aquatic insects; also eats aquatic seeds and some aquatic vegetation. Small shoal fishes often important in winter. Food obtained underwater during dives usually less than 1 minute. In some areas, nesting birds feed in lakes and ponds adjacent to their nest sites; in other areas, they make regular foraging flights to nearshore marine waters (Andres 1993).
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Population Biology
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 81 to >300
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General Ecology
Occurs singly, in pairs, or small groups. In winter off California, usually solitary or in pairs. Overall breeding density on arctic coastal plain estimated at about 1 pair per 200 ha; 5 nests observed on 1 pond of 21 ha (Johnsgard 1987). Egg predation by foxes, jaegers, and gulls sometimes is significant.
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Life History and Behavior
Reproduction
Pacific Loons are monogamous as long as the relationship is producing offspring. Breeding takes place in the spring and summer and is relatively noncompetitive once a mate is found for the males defend territories and mate with the same female each year. Loons are extremely awkward on land and venture out of the water only to nest. Broods usually include a total of two eggs, one of which is laid a few weeks before the second. This first egg also is the first to hatch, and it is brooded while the other egg is incubated. The older offspring assumes the dominant position in the nest and will be the first to be feed throughout its development. During times of inadequate food resources parents commonly continue feeding their older offspring, leading to the death of its younger sibling.
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Breeding begins in early May in south, to mid-June in north. Both adults, in turn, incubate usually 2 eggs, 28-29 days. Hatching occurs in second half of July around Beaufort Sea (Johnson and Herter 1989). Young are tended by both parents, first fly at about 2 months, independent by about 3 months. Pair-bond apparently is life-long. Nest density is up to 2.6 per sq km in Alaska (Johnson and Herter 1989).
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Molecular Biology and Genetics
Molecular Biology
Barcode data: Gavia pacifica
There are 8 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.
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Download FASTA File
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Statistics of barcoding coverage: Gavia pacifica
Public Records: 7
Specimens with Barcodes: 7
Species With Barcodes: 1
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Conservation
Conservation Status
IUCN Red List Assessment
Red List Category
Red List Criteria
Version
Year Assessed
Assessor/s
Reviewer/s
Contributor/s
Justification
History
- 2008Least Concern
- 2004Least Concern
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Pacific Loons are found in low concentrations during the winter months and in higher densities during the breeding months. This loon is combating human pressures well, but populations may decrease in the future. Recent studies are looking into the magnification of chemicals in the loon's body due to pollutants being added to the ecosystem and the loon being near the top of its food chain. The Pacific Loon's range is growing smaller as human development encroaches on its preferred habitats.
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
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National NatureServe Conservation Status
Canada
Rounded National Status Rank: N4N,N5B : N4N: Apparently Secure - Nonbreeding, N5B: Secure - Breeding
United States
Rounded National Status Rank: N5B,N4N : N5B: Secure - Breeding, N4N: Apparently Secure - Nonbreeding
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Trends
Global Short Term Trend: Unknown
Global Long Term Trend: Unknown
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Relevance to Humans and Ecosystems
Benefits
Economic Importance for Humans: Negative
Loons may be considered pests by commercial fishermen, who see them as competitors
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Economic Importance for Humans: Positive
Loons are aesthetically pleasing to observe in the nature and they are well known for their distinctive calls, which commonly occur at night.
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Wikipedia
Pacific Loon
The Pacific Loon or Pacific Diver (Gavia pacifica), is a medium-sized member of the loon, or diver, family. It may be conspecific with Black-throated Diver/Arctic Loon, which it closely resembles.
It breeds on deep lakes in the tundra region of Alaska and northern Canada as far east as Baffin Island, and in Russia east of the Lena River.
Unlike other loons/divers, this bird may migrate in flocks. It winters at sea, mainly on the Pacific coast, or on large lakes over a much wider range, including China, Japan, North Korea, South Korea, USA and Mexico. It has occurred as a vagrant to Greenland, Hong Kong, Great Britain, Spain, and Finland.[2]
Breeding adults are like a smaller sleeker version of Great Northern Diver/Common Loon. They measure 58–74 cm (23–29 in) in length, 110–128 cm (43–50 in) in wingspan and weigh 1–2.5 kg (2.2–5.5 lb).[3] They have a grey head, black throat, white underparts and chequered black-and-white mantle. Non-breeding plumage is drabber with the chin and foreneck white. Its bill is grey or whitish and dagger-shaped. In all plumages, lack of a white flank patch distinguishes this species from the otherwise very similar Black-throated Diver/Arctic Loon.
This species, like all divers/loons, is a specialist fish-eater, catching its prey underwater. It flies with neck outstretched.
The call is a yodelling high-pitched wailing, as well as harsh growls and barks.
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Habitat and range
The Pacific Loon breeds on tundra lakes, and winters in the open ocean or other large bodies of water. It breeds primarily in northern Canada and eastern Siberia, and winters along the Pacific coast of North America.[4]
References
- ^ BirdLife International (2012). "Gavia pacifica". IUCN Red List of Threatened Species. Version 2012.1. International Union for Conservation of Nature. http://www.iucnredlist.org/apps/redlist/details/106003867. Retrieved 16 July 2012.
- ^ "Pacific Loon Spotted on Finnish Lake". YLE.fi. Yleisradio Oy. November 16, 2010. http://yle.fi/uutiset/news/2010/11/pacific_loon_spotted_on_finnish_lake_2146177.html?origin=rss. Retrieved January 29, 2011.
- ^ [1] (2011).
- ^ Peterson, Roger Tory (2002). A Field Guide to the Birds of Eastern and Central North America (5 ed.). New York, NY, USA: Houghton Mifflin Harcourt. p. 9. ISBN 978-0-395-74047-7. http://books.google.com/books?id=RLj8LANp3O8C&pg=PA9.
Further reading
| Wikimedia Commons has media related to: Gavia pacifica |
The following articles deal with separation of Pacific Diver/Pacific Loon from Black-throated Diver/Arctic Loon:
- Birch, A. and Lee, C-T, 1997, Field identification of Arctic and Pacific Loons, Birding 29: 106-115.
- Birch, A and Lee, C-T, 1995, Identification of the Pacific Diver - a potential vagrant to Europe, Birding World 8: 458-466.
- Harrison, Peter (1988). Seabirds: An Identification Guide. London: Christopher Helm. ISBN 0-7470-1410-8
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Names and Taxonomy
Taxonomy
Comments: Frequently regarded as a subspecies of Arctica, but currently considered a distinct species (AOU 1985, 1998).
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