Grey Herons disperse widely after the breeding season, this movement beginning generally soon after the young can fly. Dispersal may be in almost any direction, although mainly to the southwest in Europe. In southern Europe, postbreeding migration is in September and October, and prebreeding migration in February and March (Lekuona and Campos 1996c). In northern Europe, autumn migration is from early September to late November and return is in February and April (Grishchenko and Serebryakov 1993).
Birds breeding in Scotland and England are generally non-migratory (Partridge 1986), although British birds have also been recovered in Spain and Gambia (Christmas 1994). In southern Europe, some birds remain in winter but others migrate (Lekuona and Campos 1996a, c, Marion 2000). Migration is generally to the southwest in west and east Europe, to the southwest in west Asia and to the south and southwest in east Asia (Hancock and Kushlan 1984, Li et al. 1989, Round 1995). In the Mediterranean, migration is broad but corridors occur along both the eastern and western shores. Birds nesting in Africa, India and south east Asia appear to be sedentary.
Individuals sometimes wander widely. The Grey Heron is regularly seen in Iceland, Faeroes, and Ascension islands. In the New World, it has been recorded in Greenland, United States (Burton and Smith 2001), Barbados (Smith and Smith 1990), Tobago (D. Finch 2002), French Guiana, Azores, Trinidad (F. Hayes pers. comm.), Montserrat, Martinique, off Bermuda, Brazil (Para), and Venezuela (Marion 1988). The last six records are of birds that originated in France. It has been reported offshore in South Africa (Kirsch 1998). There are also occasional records from New Guinea, Kalimatan (Van Balen 1999), Australia, and New Zealand (Parkes 1974). Early sight records from New Zealand have been discounted (Dawson 1974).
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