Although the ability of Cooper's Hawk to use altered environments has been a conservation success story, the impacts this may have on other species, including both potential prey and competitors, are little understood. For example, there is evidence that Cooper's Hawk regularly takes American Kestrel (Falco sparverius), and may contribute to the current decline of the American Kestrel in parts of its range (295, 296; K. Bildstein, unpublished data). It has also been suggested that Cooper’s Hawk may play a role in the decline of Red-Headed Woodpecker (297). This, along with other potential impacts that high populations could have, should be investigated as a matter of conservation priority.
Recent studies suggest that Sharp-shinned Hawk (Accipiter striatus) may be shortening their migration routes (a phenomenon known as "migratory short-stopping") in response to foraging opportunities presented by human landscapes (including bird feeders; see Sharp-shinned Hawk account). It seems likely that Cooper's Hawk would display similar responses to new foraging opportunities, and this possibility should also be investigated.
Recent studies have also explored the role of floaters in the adult population (67, 188). Additional studies are needed to quantify the floater population and document the role of these birds across the range.
Based on a study in New Mexico, migratory behavior, at least at some southern latitudes, is facultative (67). Additional research is needed to identify factors associated with migration that may result in a competitive advantage for resident female Cooper’s Hawks; why urban female emigrants were universally successful at securing nesting territories in a self-sustaining exurban subpopulation; and whether studies in other areas would have similar results.
Studies to help identify the causes of differences in age structure of female breeders across the country would inform much of what is currently known.
Differences in the ecology of urban Cooper’s Hawks versus their exurban and rural counterparts have been studied (187, 67). Research into selection in urban Cooper’s Hawks could lead to the potential evolution of traits that may be less adaptive in exurban habitats, as well as life-history events, such as polygyny and extra-pair copulations, that may reveal the suitability and selective pressures of city environments, would greatly add to our understanding of this species in urban settings. In addition, complementary studies in ecology, ethology and population genetics, will inform our understanding of the effect of evolutionary processes that occur in urban ecosystems (298, 187, 299).
Detailed field studies of hydrogen stable-isotope ratios of Cooper's Hawk blood, feathers, and prey, throughout the breeding season, are needed to clarify the value of stable isotopes in determining origin.