Harteman Wildfowl, presented by Jan Harteman

Ross's goose

Chen rossii (Anser rossii)

Ross'gans / Zwergschneegans  / Oie de ross

 

The Ross's Goose (Chen rossii or Anser rossii) is a North American species of goose. The American Ornithologists' Union places this species and the other two "white" geese in the genus Chen rather than the more traditional "grey" goose genus Anser.


The Ross's Goose is a rare vagrant to Western Europe, but it is commonly kept in wildfowl collections and so the true frequency of wild birds is hard to ascertain. Escaped or feral specimens are encountered frequently, usually in the company of other feral geese such as Canada GooseGreylag Goose and Barnacle Goose. However, individuals or small groups that seemed to be of natural origin have turned up in the Netherlands and Britain.


This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern (IUCN, 2009).


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Above: adult male Ross's goose


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Above: adult pair of Ross's goose


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Above: captive "Blue phase" Ross's goose in German collection


"Nobody exactly knows how the wild population of dark blue ross' evolved out of the white population, but expeditions by Walter Sturgeon and Paul Dye (International Wild Waterfowl Association) to the breeding grounds show that, by monitoring and measuring the birds, most of the qualities indicate that they evolved out of original Ross' geese." -- Ludger Brokemper, Germany



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Above: captive "Blue phase" Ross's goose


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Above: Handling an adult male Ross's goose in Vogelpark Avifauna

Photo by Jente Ottenburghs

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