Road effects on Banff National Park bird community composition and on the age distribution and health of male ruby-crowned kinglets and red-breasted nuthatches.

摘要

Roads affect bird populations in a variety of direct and indirect ways. I assessed these potential effects by comparing community diversity and attributes of individual health at sites near to (50 m) and far from (400 m) a highway and a secondary road near Banff, Canada. The health measures targeted two species -- red-breasted nuthatches and ruby-crowned kinglets -- for which I recorded age, body mass, fluctuating asymmetry and four hematological measures. Community composition differed by habitat (aspen was more diverse than pine and spruce habitats) whereas road type and road proximity had lesser and interacting effects. Proportionately more young red-breasted nuthatches lived near the highway, but no health parameter varied with road proximity for either species. Overall, the road effects I detected were slight, suggesting either that birds are not much affected by roads at this site, or that my near and far sites were equally affected by road presence.