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From Beheler et al. (2003). Note that sample sizes differ between categories.

From Beheler et al. (2003). Note that sample sizes differ between categories.

Dispersal within a breeding season

Many birds raise more than one brood per season, or attempt a second nest if the first fails, normally close by in the same territory. Some even use the same nestsites for repeat broods, especially some cavity nesters where sites are scarce. In most species, the same partners stay together for successive nests in a season but in other species some individuals change territories and partners, especially after nest failure, the female often moving further than the male (e.g. Yellow-breasted Chat Icteria virens, Thompson & Nolan 1973; House Sparrow Passer domesticus, Sappington 1977; Common Starling Sturnus vulgaris, Feare & Burham 1978; Barn Swallow Hirundo rustica, Shields 1984; Eastern Phoebe Sayornis phoebe, Beheler et al. 2003; Table 17.4).

A more extreme situation is shown by species in which some individuals raise successive broods in widely separated localities within the same breeding season (Chapter 16). Examples include some cardueline finches which feed on sporadic food supplies, settling temporarily wherever suitable seeds are plentiful, and moving elsewhere for the next nesting attempt that year (for Eurasian Bullfinch Pyrrhula pyrrhula, see Newton 2000; for Common Redpoll Carduelis flammea and Eurasian Siskin C. spinus, see Chapter 18). Other species change location part way through a breeding season, in line with changes in habitat suitability (including crop growth on farmland). For example, Eurasian Penduline Tits Remiz pendulinus studied in central Europe may raise first and second broods in different patches of riverine and lakeside scrub, as conditions change through the season, with movements generally greater than 0.5 km, and some extending up to 208 km (Franz 1988). Yet other examples include the few species (such as European Quail Coturnix coturnix) that habitually stop and breed at two or more points on a migration route (Chapter 16). In some polyandrous shorebirds, such as Eurasian Dotterel Eudromias morinellus and Kentish (Snowy) Plover Charadrius alexandrinus, the females lay one clutch for the male to incubate, and then leave in search of another male to raise a second clutch. In the process, as shown by ringing, the females can travel hundreds of kilometres between nesting attempts, with movements up to 400 km and 1140 km recorded for the two species (Mead & Clark 1988, Stenzel et al. 1994).

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