83 143 88b

81 Reynolds & Linkhart

Hiraldo et al. (1996)

The data are drawn from studies in which attempts were made to identify all individuals present. Records for different years are pooled. N = number marked, % = percentage recovered. Note the lower return rates for juveniles returning to their natal areas than for adults returning to their former breeding areas. This is due partly to higher mortality rates of juveniles, which allow fewer to return, and partly to their longer dispersal distances, which lead fewer to settle in the study area, compared with returning adults. Among established breeders, in most species return rates were higher for males than for females.

aIn most bird species nestlings cannot be sexed on morphology, but the adults can. If the nestling sex ratio is assumed to be equal, it is clear from individuals subsequently trapped in the study area that males show much greater survival or site-fidelity than females. For example, in three studies of the European Pied Flycatcher Ficedula hypoleuca, return rates of male and female nestlings were 12.4% and 8.4%, 4.4% and 3.3%, and 2.5% and 1.1% respectively (Curio 1958, Campbell 1959, von Haartman 1960). bBoth sexes included.

Table 17.2 Dispersal distances of House Wrens Troglodytes aedon in Ohio Distance away % Recoveries in later years of birds ringed as:
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