Cornish Biodiversity Network  -  Supporting Wildlife Recording

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Cornish Red Data (2009)

The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.

Anas rubripes - American Black Duck

Range & Status

Breeds Eastern North America, being a rare vagrant to the British Isles (30 records).

Regional Distribution

Cornwall: nine records of vagrants, including a drake in the vicinity of Colliford Reservoir seen intermittently from January 1999 until at least June 2007, which fathered a number of hybrids with female Mallards. Isles of Scilly: five records of vagrants, two of which arrived together; all on Tresco and all have been long-stayers. The longest was a female from October 1976 until the 1983/84 winter; she reared hybrid young in most years of her residence.

Habitat & Ecology

Fresh and brackish water, lakes and ponds, moving to lagoons and estuaries in winter. Northern populations move south in autumn, sometimes reaching Europe under adverse weather conditions.


As with Pied-billed Grebe many of the British records have involved long-staying

individuals. Hybridisation with Mallards is well known in North America and several British vagrants have produced hybrid offspring during their stays. The possibility of colonisation is perhaps unlikely with such a large population of Mallards to dilute the gene pool.


I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.

The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.