Table of Contents
Overview
Comprehensive Description
Distribution
Geographic Range
Aechmophorus occidentalis is commonly found from Canada through California, and sometimes in Mexico. It usually occurs in the great plains and western states, but occasionally can be found in the eastern half of the United States.
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: (200,000 to >2,500,000 square km (about 80,000 to >1,000,000 square miles)) BREEDS: south-central British Columbia, central Alberta, central Saskatchewan, and southwestern Manitoba, south to California, northern Utah, North Dakota, western Nebraska, northwestern Iowa, and western Minnesota; also locally in Mexico from Chihuahua and Durango south to Guerrero, Puebla, and San Luis Potosi. WINTERS: mainly along Pacific Coast from southeastern Alaska and British Columbia south to northwestern Mexico.
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Physical Description
Morphology
Physical Description
Aechmophorus occidentalis is the largest of the North American grebes, it ranges from 56-74 cm in length. It has a long neck and bill. The feet are at the far back of the body and the tail is reduced. The ankle and toe joints are very flexible to aid in manueverability in the water. The head, neck, and body are a blackish brown color from above, and white from below. The Western Grebe has a dull yellow or olive-colored bill and red eyes surrounded by dark coloration. In flight a white wing stripe is exposed. The sexes are monomorphic year round.
Aechmophorus clarkii, Clark's grebe, was only recently recognized as a separate species. Clark's grebes have white surrounding the eye and a bill that is bright yellow to orange-yellow. Their flanks have more white areas and the back is a lighter gray.
Average mass: 1400 g.
Average mass: 1475.5 g.
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Size
Ecology
Habitat
Habitat and Ecology
- Terrestrial
- Freshwater
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Habitat
Aechmophorus occidentalis is a migratory bird. It lives on freshwater lakes that have rushes and tules during the breeding season. It usualy stays on prairie lakes in British Columbia and California, and sometimes as far down as Mexico. In the winter A. occidentalis lives on the Pacific coast.
Aquatic Biomes: lakes and ponds; coastal
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Water temperature and chemistry ranges based on 85 samples.
Environmental ranges
Depth range (m): 0 - 0
Temperature range (°C): 11.144 - 15.249
Nitrate (umol/L): 0.733 - 4.675
Salinity (PPS): 30.381 - 33.476
Oxygen (ml/l): 5.880 - 6.583
Phosphate (umol/l): 0.419 - 0.800
Silicate (umol/l): 3.287 - 16.169
Graphical representation
Temperature range (°C): 11.144 - 15.249
Nitrate (umol/L): 0.733 - 4.675
Salinity (PPS): 30.381 - 33.476
Oxygen (ml/l): 5.880 - 6.583
Phosphate (umol/l): 0.419 - 0.800
Silicate (umol/l): 3.287 - 16.169
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
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Comments: Marshes, lakes, and bays; in migration and winter also sheltered seacoasts, less frequently along rivers (Subtropical and Temperate zones) (AOU 1983). Nests on large inland bodies of water. Breeding ponds/lakes in North Dakota usually have 20 ha or more of open water. Nests usually in or very close to water deep enough to allow bird to swim submerged. Nests typically is anchored to, or build up over, living vegetation (Ehrlich et al. 1992).
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Migration
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: Yes. At least some 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.
Begins departure from southernmost coastal wintering areas late March or April, moves inland by late April-early May. Migration evidently nocturnal over land, partly diurnal along coast. Apparently migrates in flocks.
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Trophic Strategy
Food Habits
Aechmophorus occidentalis is a carnivore. It mostly eats fish, but also eats insects, mollusks, and crustaceans. The Western grebe is an aggressive hunter. It dives under the water and spears fish with its long bill.
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Comments: Diet mainly fishes; opportunistic as to species eaten. Also eats insects (adults and larvae, especially in spring and summer), mollusks, crabs, marine worms, and salamanders. Ingests feathers and small stones. (Terres 1980, Johnsgard 1987). Obtains food underwater after diving from surface.
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General Ecology
Life History and Behavior
Life Expectancy
Lifespan/Longevity
Range lifespan
Status: wild: 14 (high) years.
Average lifespan
Status: wild: 132 months.
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Lifespan, longevity, and ageing
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Reproduction
Reproduction
Aechmophorus occidentalis breeds in the spring. It has a very elaborate courtship behavior. The couple will dance, posture, and run across the water. Many grebes ussually mate at the same time. The female lays three to five bluish white colored eggs. The nest floats on the water in the reeds. Both sexes take care of the young. They become very territorial during nesting. To avoid other nesting pairs the parents dive from the nest and swim underwater to go to feeding grounds.
Average time to hatching: 23 days.
Average eggs per season: 3.
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Reported average clutch size: about 2.5 in Utah, 3.4 in Colorado, 4.2 in North Dakota; dump nesting may result in large clutch in one nest. Incubation, by both adults in turn, lasts 3-4 weeks. Brood size usually is 1-3. Young are tended by both parents. Nests in colony; usually tens or hundreds of nests.
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Molecular Biology and Genetics
Molecular Biology
Barcode data: Aechmophorus occidentalis
There are 2 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: Aechmophorus occidentalis
Public Records: 1
Species: 4
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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Conservation Status
Aechemophorus occidentalis is not endangered or threatened. They are however are affected by oil spills and insecticides found in their food. The insecticides affect their breeding. Another danger to this bird is the reduction in habitat. Lakes and marshes that A. occidentalis occupies are being taken over by human development. At this time A. occidentalis hasn't been affected very much by these threats.
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: N3N,N5B : N3N: Vulnerable - Nonbreeding, N5B: Secure - Breeding
United States
Rounded National Status Rank: N5B,N5N : N5B: Secure - Breeding, N5N: Secure - Nonbreeding
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NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
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Trends
Population
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Threats
Comments: Gregarious behavior makes it highly susceptible to oiling mortality in wintering areas. Vulnerable to disturbance of nesting colonies.
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Relevance to Humans and Ecosystems
Benefits
Economic Importance for Humans: Negative
There were no negative influences found.
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Economic Importance for Humans: Positive
Aechmophorus occidentalis is of economic interest to tourists, scientists, and developers. Tourists regularly go to wildlife refuges and preserves to go birdwatching. This brings entrance fees to the wildlife parks and refuges. Scientists are interested in A. occidentalis because its habitat (the wetlands) is being taken over by development. The fact that they are still thriving shows the condition of the environment.
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Wikipedia
Western Grebe
The Western Grebe, (Aechmophorus occidentalis[2]), is a species in the grebe family of water birds. Folk names include "dabchick", "swan grebe" and "swan-necked grebe".
This is the largest North American grebe. It is 55–75 cm (22–30 in) long, weighs 795–1,818 g (1.75–4.01 lb) and measures 79–102 cm (31–40 in) across the wings.[3][4][5] It is black-and-white, with a long, slender, swan-like neck and red eyes. It is easily confused with Clark's Grebe, which shares the same features, behavior and habitat, and hybrids are known.
The Western Grebe has black around the eyes and a straight greenish-yellow bill whereas the Clark's Grebe has white around the eyes and an up-turned bright yellow bill. The downy young of Western are grey; Clark's downy young are white.
Western Grebes nest in colonies of hundreds on large inland lakes, sometimes using coastal marshes, in western North America. It has a spectacular courtship display; two birds will rear up and patter across the water's surface. Northern birds migrate west to coastal ocean in winter; birds in the southwest and Mexico may be permanent residents.
This bird dines by diving for carp, herring, mollusks, crabs, and salamanders.
Western Grebe fossils from the Late Pleistocene of SW North America were described as a distinct species (Miller 1911), but later ranked as a paleosubspecies Aechmophorus occidentalis lucasi (Howard 1946). More recent study found them to fall within the variation now known to exist in today's birds (Jehl 1967, Storer 1989).
References
- ^ BirdLife International (2008). Aechmophorus occidentalis. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 24 February 2009.
- ^ Etymology: Aechmophorus, "spear-bearer", from Ancient Greek aichme (a spear) + phoros (one who bears something around), in reference to its bill; occidentalis: Latin for "western".
- ^ [1] (2011).
- ^ [2] (2011).
- ^ CRC Handbook of Avian Body Masses by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0-8493-4258-5.
- Howard, Hildegarde (1946): A review of the Pleistocene birds of Fossil Lake, Oregon. Carnegie Institution of Washington Publications 551: 141-195.
- Jehl, Joseph R. Jr (1967): Pleistocene Birds from Fossil Lake, Oregon. Condor 69(1): 24-27 PDF fulltext
- Miller, Loye H. (1911): Additions to the avifauna of the Pleistocene deposits at Fossil Lake, Oregon. University of California Publications, Bulletin of the Department of Geology 6: 79-87.
- Storer, Robert W. (1989): The Pleistocene Western Grebe Aechmophorus (Aves, Podicipedidae) from Fossil Lake, Oregon: A comparison with Recent material. Contributions from the Museum of Paleontology, University of Michigan 27(12): 321-326. PDF fulltext
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Names and Taxonomy
Taxonomy
Comments: Light-phase birds, formerly included in this species, now regarded as distinct species, A. clarkii (Clark's grebe) (AOU 1985, 1998).
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