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THE EFFECTS OF EXPERIENCE AND BREEDING STATUS ON THE USE OF A WINTERING SITE BY BEWICK'S SWANS CYGNUS COLUMBIANUS BEWICKII
Author(s) -
Evans Mary E.
Publication year - 1980
Publication title -
ibis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 80
eISSN - 1474-919X
pISSN - 0019-1019
DOI - 10.1111/j.1474-919x.1980.tb00883.x
Subject(s) - attendance , demography , geography , seasonal breeder , winter season , biology , ecology , sociology , political science , climatology , law , geology
Summary Bewick's Swans were identified individually at Slimbridge from 1968‐69 to 1975‐76, both within one winter and from one winter to the next, by bill markings or large numbered leg rings. Units, rather than individuals, were used for analysis, each unit being placed into one of two categories (New, Experienced), and into one of four classes (family, pair, single, yearling). The Experienced category arrived proportionally earlier, had fewer one‐day attendances, stayed longer, were absent less, and departed later than the New category. Experienced families were absent more than the other Experienced classes and, in the early part of the winter, left proportionally ahead of them. Arrivals of the New classes were at different rates: yearlings built up quickest, followed by singles, pairs and families. Families had more one‐day attendance than yearlings and singles, and pairs were absent more than the other classes. The departures of the New classes, except of families, were closely synchronised. The different behaviours of the classes which determine length of stay are discussed. The birds most likely to return were those with a long attendance in a previous season.