The silvery grebe (''Podiceps occipitalis'') is a species of

grebe Grebes () are aquatic diving birds in the order (biology), order Podicipediformes (). Grebes are widely distributed freshwater birds, with some species also found in sea, marine habitats during Bird migration, migration and winter. Most grebes f ...

in the family Podicipedidae. It is found in the western and southern part of South America where it inhabits lakes and other types of open wetlands. There are two

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

, which by some recent authorities are considered separate species.

Taxonomy and subspecies

There are two subspecies, although some authorities such as the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

recognizes them as separate species: *Northern silvery grebe, ''P. o. juninensis'', ( von Berlepsch & Stolzmann, 1894) –

Andean The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18°S ...

highlands at altitudes of from

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

to north-west

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and northern

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

. *Southern silvery grebe, ''P. o. occipitalis'', ( Garnot, 1826) – at altitudes up to in central & southern parts of Chile and Argentina, and in the

Falkland Islands The Falkland Islands (; ), commonly referred to as The Falklands, is an archipelago in the South Atlantic Ocean on the Patagonian Shelf. The principal islands are about east of South America's southern Patagonian coast and from Cape Dub ...

. Partially migratory, with wintering range as far north as southern

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, southern

Bolivia Bolivia, officially the Plurinational State of Bolivia, is a landlocked country located in central South America. The country features diverse geography, including vast Amazonian plains, tropical lowlands, mountains, the Gran Chaco Province, w ...

and

Paraguay Paraguay, officially the Republic of Paraguay, is a landlocked country in South America. It is bordered by Argentina to the Argentina–Paraguay border, south and southwest, Brazil to the Brazil–Paraguay border, east and northeast, and Boli ...

Description

The silvery grebe is about in length. There are two different subspecies which differ in the colouring on their head and facial plumes. In the southern form, the ear plumes are yellowish and the side of the head and throat are grey. In the northern form, the ear plumes are grey and the side of the head and throat are white. Both have a crown that is black and the neck, chest and belly are white while the back is dark grey and the sides and flanks blackish. The beak and feet are black and the eye red. The northern form in particular is similar in appearance to the rare and highly localized Junin grebe (''Podiceps taczanowskii''), and their ranges overlap.

Distribution and habitat

The silvery grebe nests in Argentina, the Falkland Islands, Chile, and the western parts of Bolivia,

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

and Colombia. The southern silvery grebe is migratory, in winter ranging north to Paraguay, southern Bolivia and southern Brazil and possibly also in

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

. Its habitat is freshwater lakes, lagoons, reservoirs and ponds. In the

Andes The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the List of longest mountain chains on Earth, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range ...

it tends to have a preference for weakly

alkaline lake A soda lake or alkaline lake is a lake on the strongly basic side of neutrality, typically with a pH value between 9 and 12. They are characterized by high concentrations of carbonate salts, typically sodium carbonate (and related salt complexe ...

s and is sometimes found foraging on

hypersaline lake A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride, brines, and other salts, with saline levels surpassing those of ocean water (3.5%, i.e. ). Specific microbial species can thrive i ...

s. In

Patagonia Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...

, it sometimes inhabits saline lakes where it can be found in the company of

flamingo Flamingos or flamingoes () are a type of wading bird in the family Phoenicopteridae, which is the only extant family in the order Phoenicopteriformes. There are four flamingo species distributed throughout the Americas (including the Caribbe ...

es.

Biology

The silvery grebe is found in small groups and feeds on aquatic invertebrates which it catches while diving under the water. Its diet includes adults and larvae of

caddisflies The caddisflies (order Trichoptera) are a group of insects with aquatic larvae and terrestrial adults. There are approximately 14,500 described species, most of which can be divided into the suborders Integripalpia and Annulipalpia on the basis ...

, water beetles, chironomid midges and water boatmen. The silvery grebe tends to breed in colonies on lakes. The nest is often composed of floating mats of vegetation. Nesting has been recorded in February in Colombia and between September and March in Peru with most eggs being laid between November and January.

Status

The IUCN recognizes the southern and the northern silvery grebes as separate species, with the former being considered

Least Concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

and the latter

Near Threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

. Both have large ranges, but their populations are declining. This is primarily due to habitat loss, but also hunting and

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...

References

{{Taxonbar, from=Q994488 silvery grebe Birds of South America silvery grebe Taxa named by Prosper Garnot Taxonomy articles created by Polbot