Migration

Figure 2. Numbers of White-breasted and Red-breasted Nuthatches

Generally a resident species, but some western and northern populations show migratory/irruptive movements, at least in some years (e.g., Heintzelman and MacClay 1971, 1977; Miller 1979; Bradley and Bradley 1983). Heintzelman and MacClay (1971), for example, sighted nearly 300 individuals passing Bake Oven Knob Hawk Watch, PA, in autumn 1968 (Fig. 2), compared to only 53 (total) during the autumns of 1961–1967. Such irruptions are apparently localized; few migrant individuals were banded/sighted elsewhere in Pennsylvania or in nearby New Jersey during fall 1968, although > 500 Red-breasted Nuthatches (a species making more regular invasions) were netted along the coast of New Jersey that fall (Miller 1979). Smaller invasions of White-breasted Nuthatches have been recorded along the Great Lakes, especially in fall: e.g., along Ohio shore of Lake Erie (Peterjohn 1989).

In addition, there are no records of the age of these migrants, or their fate. Thus it is entirely possible that many (most?) are juveniles, “surplus” young of the year that vacate breeding areas when population numbers are high in relation to food resources. In that case, few would be expected to return to breeding areas, and in fact there is little evidence of a return spring migration in this species. The factors triggering migration of the White-breasted Nuthatch -- as well as the origin, age, and fate of migrants -- all need study.

See also Demography and Populations: range.