Aechmophorus occidentalis

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 )

Gulf of Mexico

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

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

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.

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.

Length: 64 cm

Weight: 1477 grams

Systems

• Terrestrial
• Freshwater

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

Depth range based on 13062 specimens in 1 taxon.
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.

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).

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.

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.

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.

Gregarious.

Range lifespan
Status: wild: 14 (high) years.

Average lifespan
Status: wild: 132 months.

Maximum longevity: 14 years (wild)

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.

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.

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

There are 3 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.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Specimens with Barcodes: 4
Species With Barcodes: 1

Canada

Rounded National Status Rank: N5B,N3N : N5B: Secure - Breeding, N3N: Vulnerable - Nonbreeding

United States

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

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2008
  Least Concern
• 2004
  Least Concern

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

Rounded Global Status Rank: G5 - Secure

Population

Comments: Gregarious behavior makes it highly susceptible to oiling mortality in wintering areas. Vulnerable to disturbance of nesting colonies.

There were no negative influences found.

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.