Jc 1000 -ig si


These birds migrate between eastern North America and Central or South America, but species that breed nearest to California are those most often seen there. Other groups of birds, which are more or less mobile than warblers, show different levels of vagrancy, but again distance from regular range has a major influence, as does prevailing wind direction (De Sante 1983a). Another factor of likely importance to occurrence is body size, if only because larger birds can fast for longer than small ones, and are thus more likely to survive a difficult journey. Relative to their population sizes, large vagrants (such as ducks) seem to turn up more often than smaller ones (such as warblers), but I know of no formal analysis of this aspect. As explained later, however, there are notable exceptions to all these general trends, and almost certainly, the majority of long-distance overwater vagrants end up as fish-food.

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