Mark R. Fuller
Kimberly Titus
1990
<p>Using simple regression, pooled-sites route-regression, and nonparametric rank-trend analyses, we evaluated trends in counts of hawks migrating past 6 eastern hawk lookouts from 1972 to 1987. The indexing variable was the total count for a season. Bald eagle (<i>Haliaeetus leucocephalus</i>), peregrine falcon (<i>Falco peregrinus</i>), merlin (<i>F. columbarius</i>), osprey (<i>Pandion haliaetus</i>), and Cooper's hawk (<i>Accipiter cooperii</i>) counts increased using route-regression and nonparametric methods (P < 0.05). Northern harrier (<i>Circus</i> <i>cyaneus</i>) counts increased based on the nonparametric method (P < 0.01) but not the route-regression method (P > 0.10). We found no consistent trends (P > 0.10) in counts of sharp-shinned hawks (<i>A. striatus</i>), northern goshawks (<i>A. gentilis</i>) red-shouldered hawks (<i>Buteo lineatus)</i>, red-tailed hawks (<i>B. jamaicensis</i>), rough-legged hawsk (<i>B. lagopus</i>), and American kestrels (<i>F. sparverius</i>). Broad-winged hawk (<i>B. platypterus</i>) counts declined (P < 0.05) based on the route-regression method. Empirical comparisons of our results with those for well-studied species such as the peregrine falcon, bald eagle, and osprey indicated agreement with nesting surveys. We suggest that counts of migrant hawks are a useful and economical method for detecting long-term trends in species across regions, particularly for species that otherwise cannot be easily surveyed.</p>
application/pdf
10.2307/3809660
en
Wiley
Recent trends in counts of migrant hawks from northeastern North America
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