Editing Western grebe

{{short description|Species of bird}}
{{Speciesbox
| name = Western grebe
| image = Western Grebe swimming.jpg
| image_alt = Western grebe swimming in blue water facing left. Its reflection is slightly distorted by ripples in the water.
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=BirdLife International |date=2019 |title=''Aechmophorus occidentalis'' |volume=2019 |page=e.T22696631A139355294 |doi=10.2305/IUCN.UK.2019-3.RLTS.T22696631A139355294.en |access-date=12 November 2021}}</ref>
| genus = Aechmophorus
| species = occidentalis
| authority = ([[George Newbold Lawrence|Lawrence]], 1858)
| synonyms =
*''Aechmophorus lucasi''<br/><small>[[Loye H. Miller|Miller]], 1911</small>
*''Aechmophorus occidentalis lucasi''<br/><small>[[Loye H. Miller|Miller]], 1911</small>
*''Aechmophorus occidentalis occidentalis''<br/><small>(Lawrence, 1858)</small>
| range_map = Aechmophorus occidentalis map.svg
| range_map_caption = Approximate distribution map
{{leftlegend|#f18e08|Breeding}}
{{leftlegend|#ffd42a|Migration}}
{{leftlegend|#7162c8|Year-round}}
{{leftlegend|#5f9ed3|Nonbreeding}}
}}

The '''western grebe'''<ref>{{cite web|title=Western Grebe|url=https://birdsna.org/Species-Account/bna/species/wesgre/foodhabits/|website=Birds of North America|publisher=Cornell Lab of Ornothology|access-date=7 April 2017}}</ref> ('''''Aechmophorus occidentalis''''')<ref>[[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".</ref> is a [[species]] in the [[grebe]] family of water [[bird]]s. Folk names include "dabchick", "swan grebe" and "swan-necked grebe".

Western grebe fossils from the [[Late Pleistocene]] of southwest North America<!-- Auk90:483; Condor51:20;69:24 --> were described as a distinct species,<ref name=Miller/> but later ranked as a [[paleosubspecies]] ''Aechmophorus occidentalis lucasi''.<ref name=Howard/> More recent study found them to fall within the variation now known to exist in today's birds.<ref name=Jehl/><ref name=Storer/>

==Description==
The western grebe is the largest [[North America]]n grebe. It is {{convert|55|-|75|cm|in|abbr=on}} long, weighs {{convert|795|-|2000|g|lb|abbr=on}} and measures {{convert|79|-|102|cm|in|abbr=on}} across the wings.<ref>[http://www.allaboutbirds.org/guide/Western_Grebe/lifehistory Western Grebe]. All About Birds</ref><ref name = "CRC">''CRC Handbook of Avian Body Masses'' by John B. Dunning Jr. (Editor). CRC Press (1992), {{ISBN|978-0-8493-4258-5}}.</ref><ref name="Burnie">Burnie D and Wilson DE (Eds.), ''Animal: The Definitive Visual Guide to the World's Wildlife''. DK Adult (2005), {{ISBN|0789477645}}</ref> 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 similar features, body size, behavior and habitat, and [[Hybrid (biology)|hybrids]] are known. Western grebes nest in colonies on lakes that are mixed with marsh vegetation and open water. Western Grebe nests are made of plant debris and sodden materials, and the nest-building begins roughly around late April through June. The construction is done by both sexes and is continued on throughout laying and incubation.<ref>Mills, Kyra (2016)., "Post-Release Survival and Movement of Western Grebes (Aechmophorus occidentalis) Implanted with Intracoelomic Satellite Transmitters" {{ISSN|1524-4695}}</ref> This species of waterbirds is widespread in western North America, so there is no specific place of abundance. Its subspecies, Clark's grebe generally populate more of the southern part of North America <ref name="Kenn, Kaufman 2007">Kenn, Kaufman (2007)., Western Grebe. Birder's World, 21(6), 40–42.</ref> Other differences are whiter flanks and paler gray backs when comparing A.o.clarkii to A.o.occidentalis.<ref name="Ratti, J. T. 1979">Ratti, J. T. (1979). Reproductive Separation and Isolating Mechanisms between Sympatric Dark- and Light- Phase Western Grebes. American Ornithological Society, 93(3), 573–586.</ref> 
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.
<gallery mode=packed>
Western Grebe.jpg|alt=A western grebe walking on the shallows near a body of water|Out of the water
Aechmophorus occidentalis-swimming.jpg|alt=A western grebe swimming|Swimming
</gallery>

===Subspecies===

In 1858 [[George Newbold Lawrence]] recognised ''Podiceps occidentalis'' based on darker coloured specimens, and ''P. clarkii'' based on three paler coloured specimens -two from California and one from [[Chihuahua (state)|Chihuahua]]. These two colour [[Polymorphism (biology)|morphs]] were found to occur, roost and even interbreed together, and were long regarded to be synonyms (although it is unclear why ''P. clarkii'' was regarded as the junior synonym, coming alphabetically first). Deignan designated the Mexican specimen as the [[holotype]] of the taxon ''P. clarkii'' in 1961. In 1963 Dickerman reinstated the taxon as ''[[Aechmophorus clarkii]]'', which he defined as the smaller birds, both dark and pale coloured, from Mexico. In 1979 a comprehensive study by Ratti demonstrated the apparent existence of reproductive barriers between different phases of the grebes. In 1986 Dickerman recognised the taxonomic significance of the distinctions between the dark and pale phase, and classified these phases as different subspecies:<ref name=Ratti1979>{{cite journal |last=Ratti |first=John T. |date=July 1979 |title=Reproductive Separation and Isolating Mechanisms Between Sympatric Dark- and Light-phase Western Grebes |url=https://sora.unm.edu/sites/default/files/journals/auk/v096n03/p0573-p0586.pdf |journal=The Auk |volume=96 |pages=573–586 |access-date=25 November 2018}}</ref><ref name=Dickerman1986>{{cite journal |last=Dickerman |first=Robert W. |date=1986 |title=Two Hitherto Unnamed Populations Of Aechmophorus (Aves: Podicipitidae) |url=https://www.biodiversitylibrary.org/page/34595906#page/463/mode/1up |journal=Proceedings of the Biological Society of Washington |volume=99 |pages=435–436 |access-date=25 November 2018}}</ref>

*''A. occidentalis'' ssp. ''occidentalis'', <small>([[George Newbold Lawrence|Lawrence]], 1858)</small>, large, dark morph, from western Canada & United States (California, Utah)
*''A. occidentalis'' ssp. ''ephemeralis'', <small>Dickerman, 1986</small> - Smaller than the western grebe, dark morph, from north & central Mexico.
*''A. clarkii'' ssp. ''clarkii'', <small>([[George Newbold Lawrence|Lawrence]], 1858) Dickerman, 1963</small> - Small, pale morph, from north & central Mexico
*''A. clarkii'' ssp. ''transitionalis'', <small>Dickerman, 1986</small>, large, pale morph, from western Canada & United States (California, Utah)

Multiple lines of evidence suggest that the differently colored western grebes (darker and lighter) are different taxa -in a single population in which sympatric speciation somehow persists. These forms were reported to mate according to their own colors and the mixing between dark and light-faced individuals is rare.<ref name="Ratti, J. T. 1979"/> This type of assortative mating derives from possible isolating mechanisms such as differential responses to advertising calls and spatial distribution.<ref name="Ratti, J. T. 1979"/><ref>Storer, R. W., & Nuechterlein, G. L. (1985). Analysis Of Plumage and Morphological Characters of the Two Color Forms of the Western Grebe (Aechmophorus). American Ornithological Society, 102(1), 102–119.</ref> Each of the forms tended to stay closer to their own type, thus making their colony nesting be non-randomly distributed.<ref name="Ratti, J. T. 1979"/>

By 1992 Storer & Nuechterlein were promoting another concept to the taxon ''A. clarkii'', now regarding the pale morphs from the US and Canada to be this taxon (Dickerman's ''A. occidentalis'' ssp. ''ephemeralis'').<ref name=Storer1992>{{cite journal |title=Clark's Grebe (Aechmophorus clarkii) |url=https://birdsna.org/Species-Account/bna/species/clagre/foodhabits |journal=The Birds of North America Online |last1=Storer |first1=Robert W. |last2=Nuechterlein |first2=Gary L. |date=1992 |publisher=Cornell Lab of Ornothology, Ithaca, New York, USA |doi=10.2173/bna.26b |access-date=7 April 2017|url-access=subscription }}</ref>

==Breeding==
[[File:Rushing Western Grebes .jpg|alt=Two western grebes moving astride one another as part of their complex courtship behavior.|thumb|Rushing western grebes in courtship]]
Western grebes nest in colonies of hundreds on large inland [[lake]]s, sometimes using [[coast]]al [[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]] [[bird migration|migrate]] west to [[coastal]] [[ocean]] in winter; birds in the southwest and Mexico may be permanent residents. During the breeding season, the birds advertise themselves through ceremonies. Rushing Ceremony, which can be also called as water dance, race or run, is a ceremony that is the most frequent display to form a pair-bond. This is performed in pairs of either both male Western grebes or one male and one female. One of two individuals initiates Rushing, and the paired individual follows immediately and performs in synchrony. The birds lift their wings stiffly to the side and run in an upright position with its head held forward and neck curved. The males seem to perform the rushing together to attract the attention of females, and when one of two males attracts a female from his rushing behavior, a competition arises between males to get the female. One out of two withdraw and the "winning" male mates with the female by performing Rushing together and continue to perform Weed Ceremony.<ref name="Nuechterlein, G. L. 1982">Nuechterlein, G. L., & Storer, R. W. (1982). The Pair-Formation Displays of the Western Grebe. American Ornithological Society, 84(4), 351–369.</ref>
Weed Ceremony usually precedes the acts of mating and nest building. It is done after the pair is formed, and the ceremony begins as the mates bob their heads in water. Then they dive in place and come back up to surface while holding weed on their beaks. This ceremony is continued until one of the pair flips away its weeds and drops to a normal position in water. They continue their mating with Greeting Ceremony. Greeting ceremony is similar to the form of rushing ceremony and involves dip-shaking, bob-shaking, bob-preening and arch-clucking.<ref name="Lindsay, S. 2007, pp. 8">Lindsay, S. (2007, September 8). Elegant Western Grebes; Elaborate Mating Rituals Evoke Thoughts of Dance. The Spokesman-Review, pp. 8</ref> Dip-shaking consists of dipping the head in the water and raising it up while rapidly waggling the bill side to side. This involves a low neck posture and conspicuous water splash while bob-shaking does not.<ref name="Nuechterlein, G. L. 1982"/> These breeding dances are known to be the most elaborated dances in the waterbird species.<ref name="Lindsay, S. 2007, pp. 8"/> 
After the breeding, the male Western Grebes feed their mate, thus performing mate feeding behavior. The feeding resembles the feeding of the young by parents, and through the feeding they obtain, females are able to have enough energy to form their eggs. During the incubation period, male and female Western Grebes trade places to incubate their eggs for weeks, and those that are not incubating feed their mate.<ref>Nuechterlein, G. L., & Storer, R. W. (1989). Mate Feeding by Western and Clark's Grebes. American Ornithological Society, 91(1), 37–42.</ref>

==Communication style==
When tending their young, Western grebe parents use different types of vocalization to communicate. Ticking is one of the two and is used as an alarm signal. Parents carry their newly hatched young on their backs, and when the parents make a ticking sound, this is used as a signal for their chicks to hide their heads beneath the back of their parents and be silent. If chicks are greater than 4 weeks of age, they respond to the ticking by swimming or diving away on their own. When making a ticking sound, the callers do not open their mouths, so it is hard to distinguish who is the maker of the sound. The parent who carries the chicks tend to make the ticking sound more often than those that do not, and both of male and female parents are equally likely to tick. Another vocalization noise is clucking, and this signals for food. When a parent clucks, the young respond to it by poking their head out of their parent back where they are on to receive food.<ref>Nuechterlein, G. L. (1988). Parent-Young Vocal Communication in Western Grebes. American Ornithological Society, 90(3), 632–636.
</ref>

==Reproduction and survival==
[[File:Western grebes and young (15762964143).jpg|thumb|alt=Two western grebes, one in a nest, another approaching the nest. Both grebes are carrying baby grebes on their backs.|Western grebes nesting with young]]
The clutch size decreases as the mating season progresses, meaning if the mating is done at the last of days in mating season, the number of offspring produced is smaller.<ref name="Robison, K. M. 2014">Robison, K. M., Anderson, D. W., & Robison, R. E. (2014). Brood Size and Nesting Phenology in Western Grebe (Aechmophorus occidentalis) and Clark's Grebe (Aechmophorus clarkii) in Northern California. BioOne, 38(1), 99–105.</ref> However it is also stated brood size of nests that hatched later in the season is larger than those from earlier, which contradicts previous findings.<ref name="Robison, K. M. 2014"/> This may be due to ecological constraints. Ecological constraints also pressure the young, and this may lead to siblicide in the first weeks after hatching, which may explain the brooding differences.<ref name="Robison, K. M. 2014"/> Also, Western grebes are sensitive to humans, such that when there is human disturbance near them, the parents leave their nest, leaving their unhatched eggs vulnerable to attacks by predators. This shows the predation or even the seemingly threatening acts result in a decrease of reproduction and survival of the young.<ref>Seattle Audubon Society (n.d.). Western Grebe. Retrieved from [http://birdweb.org/birdweb/bird/western_grebe].</ref> Because they are so sensitive, there have been restoration efforts to rebuild the Western grebes' native habitats, so that they have greater opportunity to reproduce and raise their young without disturbance or threat. The number of Grebes has been slowly declining in the last two decades, not only because of predation, but also because of [[habitat destruction]], with oil spillage being one of the major causes.<ref>Mills, K. L., Gaydos, J. K., Fiorello, C. V., Whitmer, E. R., De La Cruz, S., Mulcahy, D. M., … Ziccardi, M. H. (2015). Post-Release Survival and Movement of Western Grebes (Aechmophorus occidentalis) Implanted with Intracoelomic Satellite Transmitters. Waterbirds, 39(2), 175–186.</ref>

==Food and feeding==
This bird dives for [[carp]], [[herring]], [[mollusk]]s, [[crab]]s, and [[amphibian]]s, such as [[salamander]]s. It often peers below the water before diving. Recent observations suggest that the grebe dives at the bottom of the lake. Some smaller fish are impaled much like [[herons]], with the bill, but others are grasped. Most are swallowed underwater, but some are brought to the surface, pinched, and swallowed.<ref name=Mills>{{cite journal|author=Mills, Kyra|author-link=Mills, Kyra|year=2016|title= Post-Release Survival and Movement of Western Grebes (Aechmophorus occidentalis) Implanted with Intracoelomic Satellite Transmitters|journal=Waterbirds|volume=39|issue=2|pages= 175–186|doi=10.1675/063.039.0208|s2cid=88653499}}</ref>

==References==

{{Reflist|refs=
<ref name=Howard>{{cite journal|author=Howard, Hildegarde|author-link=Howard, Hildegarde|year=1946|title= A review of the Pleistocene birds of Fossil Lake, Oregon|journal=Carnegie Institution of Washington Publications|volume=551|pages= 141–195}}</ref>
<ref name=Jehl>{{cite journal|author=Jehl, Joseph R. Jr |year=1967|title= Pleistocene Birds from Fossil Lake, Oregon|journal=[[Condor (journal)|Condor]]|volume=69|issue=1|pages= 24–27 |url=http://sora.unm.edu/sites/default/files/journals/condor/v069n01/p0024-p0027.pdf|doi=10.2307/1366369|jstor=1366369}}</ref>
<ref name=Miller>{{cite journal|author=Miller, Loye H. |year=1911|title= Additions to the avifauna of the Pleistocene deposits at Fossil Lake, Oregon|journal=University of California Publications, Bulletin of the Department of Geology|volume=6|pages= 79–87}}</ref>
<ref name=Storer>{{cite journal|author=Storer, Robert W. |year=1989|title= The Pleistocene Western Grebe ''Aechmophorus'' (Aves, Podicipedidae) from Fossil Lake, Oregon: A comparison with Recent material|journal=Contributions from the Museum of Paleontology, University of Michigan|volume=27|issue=12|pages= 321–326|url=http://deepblue.lib.umich.edu/dspace/bitstream/2027.42/48534/2/ID387.pdf}}</ref>
}}

==Further reading==
*{{cite magazine|title=The Birds That Walk on Water|magazine=[[National Geographic (magazine)|National Geographic]]|first=Gary L.|last=Nuechterlein|pages=624–637|volume=161|issue=5|date=May 1982|issn=0027-9358|oclc=643483454}}

==External links==
{{Commons category|Aechmophorus occidentalis|Western Grebe}}
{{Wikispecies|Aechmophorus occidentalis}}
* [http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Western_Grebe.html Western Grebe Species Account] - Cornell Lab of Ornithology
* [http://www.mbr-pwrc.usgs.gov/id/framlst/i0010id.html Western Grebe - ''Aechmophorus occidentalis''] - USGS Patuxent Bird Identification InfoCenter
* {{usurped|1=[https://web.archive.org/web/20001025142529/http://www.bird-stamps.org/cspecies/901800.htm Stamps]}} (for Canada) at bird-stamps.org
* {{ITIS | id=174503 | taxon=''Aechmophorus occidentalis'' | access-date=24 February 2009 }}
* {{InternetBirdCollection|western-grebe-aechmophorus-occidentalis|Western Grebe}}
* {{VIREO|Western+Grebe|Western Grebe}}

{{Grebes}}

{{Taxonbar|from=Q679154}}

[[Category:Aechmophorus]]
[[Category:Podicipedidae]]
[[Category:Birds of North America]]
[[Category:Birds of Canada]]
[[Category:Birds of the United States]]
[[Category:Birds of Mexico]]
[[Category:Birds described in 1858]]
[[Category:Taxa named by George Newbold Lawrence]]