Figure 23.8 Mean distance (±SE) from ringing to recovery sites for adult Common Grackles Quiscalus quiscula (N = 855) and Common Starlings Sturnus vulgaris (N = 1116), illustrating telescopic migration in two species ringed on their breeding areas in eastern North America (75-100° longitude), and recovered in winter (January-February) further south, in a narrower span of latitude. In both species, birds from more northern breeding areas travelled further, on average, but wintered in the same latitudinal band as birds from more southern breeding areas. From Dolbeer (1982).
In chain migration, the distances may be more or less similar among populations, even though these populations migrate between different areas, but in the other two latitudinal patterns the high-latitude populations migrate furthest, with the greatest population differences occurring in leapfrog migrants. It is impossible to say from the data available how common these different patterns of latitudinal segregation are among migrants, or whether they differ in frequency between regions. These questions could best be answered by comprehensive widescale analyses of ring recoveries.
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