OVERVIEW
Taxonomy
- Class – Aves (like all birds)
- Order – Podicipediformes (meaning “rear foot” in Latin, their legs are closer to the back than the front to help with diving and swimming, but not so great for walking)
- Family – Podicipedidae
- Genus – Aechmophorus (meaning “spear-bearing” in Greek, for their stabby bill)
- Species – occidentalis
Identification
Usually found sporting an elegant black and white tuxedo on its swan-like neck, a dark cap that extends below fiery red eyes and meets a bill of dull olive-yellow.
Not to be confused with similar-looking species: Clark’s Grebe (black cap does not extend below the eye) or non-breeding Red-necked Grebe (eyes are black, neck is gray-washed, and flanks have more white feathers). Hybrids of Western and Clark’s Grebes also occur on occasion, making them VERY close relatives. (CLO, 2020)
Males and females look practically the same, although females tend to have a slightly smaller bill. Western Grebes live up to 8 -11 years, are roughly crow-sized (2-ft long by 2-ft wide wingspan), and weigh approximately 1 to 1.8 kg. (BirdLife, 2019 & CLO, 2020)
Not so fun fact: Their dense and waterproof plumage was so coveted in the nineteenth century, that grebes were hunted to endangerment in the name of fashion. (CLO, 2020)
HABITAT DISTRIBUTION
Endemic to western North America, the range of Western Grebes extends as far east as Manitoba. Of the Canadian population, less than 2% reside in BC, 60% live in Alberta, 10% in Saskatchewan, and 30% in Manitoba (ECCC, 2022). In the spring and summer, they breed in inland lakes and wetlands, then migrate back in the fall to warmer coastal areas (left image below). A single large lake may contain a colony of hundreds of mating pairs. (CLO, 2020). The image on the right shows the frequency of sightings for a set of 700,000 recorded observations (eBird, 2024).
BEHAVIOUR
As excellent swimmers with lobbed toes, they spend most of their time in the water, where they dive for prey, eat, rest, and nest, not necessarily in that order. (CLO, 2020). And graceful as they may seem, they can be slightly awkward outside of their natural element:
Reproduction
Ever sticklers for romance, Western Grebe mates employ two sequential courtship displays referred to as “ceremonies” (CLO, 2020). But first, sit back and enjoy the relaxing sound of gears grinding, err, courtship: (Audubon)
1) Rushing ceremony – it begins with a shrill “kreet-kreet”, followed by bill dips, head shaking, dancing, then finish off with a sudden dive. The “Rush” is performed by either mating pairs or males trying to show off, as seen in BBC Life: The Grebes (narrated by the one and only, David Attenborough).
Don’t quote me on this, but I’m pretty sure J.T. got inspired for his dance moves by Western Grebes’ rushing ceremony. (YouTube)
2) Weed ceremony – this one involves neck stretching and yes, “weed-dancing”, in which the mating pair dives down in the lake, then they both come up to spiral around one another with a bill-full of weeds, if that’s not romance then I don’t know what is. (CLO, 2020)
Nesting & Brooding
After their impressive ritual, the mating pair build (or steal) floating nests on emergent vegetation such as rushes and reeds, typically in waters that are less than one metre deep. (Audubon, 2024). They are quick to exploit recently abandoned empty nests within a colony, to avoid the heavy cost of building a new one (Hayes & Turner, 2017).
Eggs are pale bluish-white to brown, and get incubated for about one month. (CLO, 2020)
A clutch may have anywhere from 2 to 6 eggs. (Audubon, 2024)
Hatchlings are carried on their parents’ back, and fed a diet of insect larvae and small fish. (CLO, 2020)
As they continue to grow into adults, their diet transitions into crustaceans, aquatic worms, insects and larger fish (CLO, 2020).
After only a few weeks (and some futile begging), they are free to dive and feed on their own, having grown their formative (juvenile) plumage. (CLO, 2020). By 10 weeks-old, they can generally spread their wings and take flight (Audubon, 2024).
Fun fact about preening: They sometimes swallow their own feathers, but not to worry, they serve a purpose to protect the stomach lining from possible punctures from fish bones, and they are afterwards regurgitated with grace (CLO, 2020).
CONSERVATION STATUS
| Jurisdiction | Status | Agency (Year) |
|---|---|---|
| Provincial (BC) | Red List (At Risk), S1S2 – critically imperiled to imperiled | NatureServe (2023) |
| Federal (Canada) | SC – Special Concern | COSEWIC (2014) & SARA (2017) |
| Global | Least Concern (LC) | IUCN (2019) |
Western Grebes are federally protected under the Migratory Birds Convention Act of 1994, and under the United States Migratory Bird Treaty Act, since the majority of the population winters in warmer U.S. regions (ECCC, 2022).
Global population is estimated at 100,000 individuals, with 30% residing in Canada. (ECCC, 2022). Within their colonies, population density is roughly 70 individuals per square-kilometre (COSEWIC, 2014).
One of the main conservation challenges includes habitat loss of nesting grounds due to more frequent wildfires and human disturbance (Audubon, 2024). Grebes are also susceptible to water level fluctuations, chemicals in their environment (mainly pesticides and oil), marine vessel disturbances, gill nets, and collisions with energy infrastructure such as powerlines and wind turbines (ECCC, 2022, Fox et. al, 2016, & CLO, 2020).
IN CULTURE
In Ojibwe oral tradition, Grebe is given the name of “Hell-Diver” for their ability to withstand harsh conditions set by the Spirit of Winter, through resourceful diving. Hell-Diver’s care for their friends, mallard and crane, feeds a fire that eventually brings the onset of spring. (Milwaukee Public Museum, 2022).
LATEST RESEARCH
Drone Surveys Aid Habitat Conservation
Drone surveys help with investigations of nest surveys in inland aquatic habitats. In a study by McKellar (2022), high-resolution imagery showed areal coverage of rooted aquatic vegetation in wetlands. As predicted, decreasing areas of open water correlated with more crowded nesting sites (pink dots on the left image above) for Western Grebes, who compete for sites that are far away enough from shore to avoid predation.
This provided an insight into the advantages or disadvantages of grebes aggregating into bigger colonies. In conjunction, ground-based surveys provide a fitness measurement based on survival rates of eggs and juveniles. This remote monitoring application has the potential to identify changing habitats at targeted areas from an aerial perspective on a more frequent basis, which would facilitate real-time implementation of conservation measures.
Another study that used drone surveys demonstrated that nesting Western Grebes prefer intermediate water depths in any given body of water, within a depth range of 40-80 cm. (Lachman et. al, 2022).
In wetland areas that are both limited by ground-access, and visually cryptic from an aerial perspective, drones with dual visible-thermal cameras managed to accurately identify nest sites with eggs based on their heat signatures, with results that were within 5% of a ground-based survey that was conducted in synchronicity (McKellar et. al, 2021- image on the right).
Lachman (2020) makes a point that drone surveys should be specific to fit the requirements of each site and species. These are feasible due to the lower cost and ease of deployment of drones, increasing image resolution and capabilities, and a less invasive method by avoiding interactions with resident waterfowl.
REFERENCES
BirdLife International (BirdLife) (2019). Western Grebe: Aechmophorus occidentalis. The IUCN Red List of Threatened Species. Retrieved September 2024, from https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T22696631A139355294.en.
British Columbia Conservation Data Centre (BC CDC) (2024). BC Species and Ecosystems Explorer. B.C. Ministry of Environment. Retrieved September 2024, from https://a100.gov.bc.ca/pub/eswp/
Cornell Lab of Ornithology (CLO) (2020). Western Grebe. All About Birds. Retrieved September 2024, from https://www.allaboutbirds.org/guide/Western_Grebe/
COSEWIC (2014). COSEWIC assessment and status report on the Western Grebe, Aechmophorus occidentalis, in Canada. Committee on the Status of Endangered Wildlife in Canada. Retrieved September 2024, from https://publications.gc.ca/site/eng/466562/publication.html
eBird (2020). Western Grebe (Aechmophorus occidentalis). The Cornell Lab of Ornithology. Retrieved September 2024, from https://ebird.org/species/wesgre
Environment and Climate Change Canada (ECCC) (2022). Management Plan for the Western Grebe (Aechmophorus occidentalis) in Canada. Species at Risk Act Management Plan Series. Retrieved September 2024, from https://wildlife-species.az.ec.gc.ca/species-risk-registry/virtual_sara/files//plans/mp_western_grebe_e_final.pdf
Fox, C. H., O’Hara, P. D., Bertazzon, S., Morgan, K., Underwood, F. E., & Paquet, P. C. (2016). A preliminary spatial assessment of risk: Marine birds and chronic oil pollution on canada’s pacific coast. Science of the Total Environment, 573, 799-809. https://doi.org/10.1016/j.scitotenv.2016.08.145
Hayes, F. E., & Turner, D. G. (2017). Copulation Behavior in Western Grebe (Aechmophorus occidentalis) and Clark’s Grebe (Aechmophorus clarkii). Waterbirds (De Leon Springs, Fla.), 40(2), 168-172. https://doi.org/10.1675/063.040.0209
Howie, R. (2015). Western Grebe. In P.J.A. Davidson, R.J. Cannings, A.R. Couturier, D. Lepage, and C.M. Di Corrado (Eds.), The Atlas of the Breeding Birds of British Columbia, 2008–2012. Bird Studies Canada. Retrieved September 2024, from http://www.birdatlas.bc.ca/accounts/speciesaccount.jsp?sp=WEGR&lang=en
Lachman, D. A., Conway, C. J., Vierling, K. T., Matthews, T., & Mack, D. E. (2022). Drones and bathymetry show the importance of optimal water depth for nest placement within breeding colonies of western and Clark’s Grebes. Wetlands (Wilmington, N.C.), 42(8), 110. https://doi.org/10.1007/s13157-022-01602-1
Lachman, D., Conway, C., Vierling, K., & Matthews, T. (2020). Drones provide a better method to find nests and estimate nest survival for colonial waterbirds: A demonstration with western grebes. Wetlands Ecology and Management, 28(5), 837-845. https://doi.org/10.1007/s11273-020-09743-y
McKellar, A. E. (2022). Patterns of inter- and intraspecific nest dispersion in colonies of gulls and grebes based on drone imagery. Journal of Field Ornithology, 93(2), 4. https://doi.org/10.5751/JFO-00099-930204
McKellar, A. E., Shephard, N. G., Chabot, D., Horning, N., & Mulero‐Pazmany, M. (2021). Dual visible‐thermal camera approach facilitates drone surveys of colonial marshbirds. Remote Sensing in Ecology and Conservation, 7(2), 214-226. https://doi.org/10.1002/rse2.183
Milwaukee Public Museum (2022). Ojibwe Oral Tradition. Retrieved September 2024, from https://www.mpm.edu/content/wirp/ICW-141
National Audubon Society (Audubon) (2024). Western Grebe. Retrieved September 2024, from https://www.audubon.org/field-guide/bird/western-grebe
Sibley, D. A. (2016). The Sibley field guide to birds of western North America. (2nd ed.). Alfred A. Knopf.
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