Concluding Remarks

If bird vagrancy were an entirely random process, birds could in theory turn up anywhere at anytime, but with a probability that declined with increasing distance from the regular range. However, random processes could not explain why almost all vagrants derive from migratory species, which turn up at migration seasons, often in specific localities year after year and in association with specific weather patterns. Nor can it explain why several species from the same region

Table 10.6 Some interesting transatlantic ring recoveries of vagrants (excluding pelagic species and regular transatlantic migrants; see Table 10.5 footnote)

Species

Ringing site

Recovery site

Black-crowned Night Heron Nycticorax nycticorax

New York, 11 June 1988

Azores, 16 October 1988

Little Blue Heron Egretta caerulea

New Jersey, 26 June 1964

Azores, November 1964

Peregrine Falcon Falco peregrinus

New Brunswick, 18 July 1986

England, 24 December 1986

American Coot Fulica americana

Ontario, 30 August 1971

Azores, 25 October 1971

Upland Sandpiper Bartramia longicauda

Michigan, 5 July 1988

Spain, 2 December 1988

Common Tern Sterna hirundo

Massachusetts, 3 July 1956

Azores, October 1964

Common Tern Sterna hirundo

Massachusetts, 12 July 1986

France, 26 October 1986

Caspian Tern Sterna caspia

Michigan, 14 July 1927

England, August 1939

Wood Duck Aix sponsa

North Carolina, 11 August 1984

Azores, August 1985

Northern Pintail Anas acuta

Labrador, 19 August 1948

England, 15 September 1948

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