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It is well known that North American grassland bird populations appear to be declining (Igl and Johnson 1997, Sauer et al. 2004). Most of these birds breed and winter in North America, so declines are likely associated with continental processes (Knopf 1994). Scientists have also observed parallel declines among species that have overlapping breeding ranges but disparate wintering distributions (Igl and Johnson 1997). These patterns suggest declines may be linked to problems on the breeding grounds.