PARENT SESSION
Oral Session # 67: Urban Ecology I: Dynamics, Values, and Systems.
Presiding: A Yeakley
Thursday, August 7. 8:00 AM to 11:30 AM, SITCC Meeting Room 105.
Life history attributes of bird communities along an urban gradient: Does nesting success influence species composition?
Blair, Robert*,1, Reale, Joseph2, 1 Dept of Fisheries, Wildlife, and Conservation Biology, St. Paul, MN, USA2 City of Boulder, Boulder, CO, USA
ABSTRACT- The increase in urbanization in North America has raised concerns regarding impacts on avian populations. In this study, we assessed the life history attributes of birds along an urban gradient in southwestern Ohio. We found that the number of species that use a multiple-brood breeding strategy increases with urbanization. Further, birds identified as high-nesting species reached peak levels at the most natural sites and decrease in number with the urbanization. In contrast, low-nesting species exhibited the reverse trend. These findings suggested that nesting success may drive the distribution of avian species along an urban gradient. To investigate this, we measured the nesting success of American robins and Northern cardinals and analyzed the changes along the gradient. We found that nesting failure was not significantly correlated with location on the gradient, but was correlated to the height of the nest, which decreased significantly from the most natural to the most urban sites. Further, the density of adult birds did not predict nesting failure. These findings suggest that nesting site is a critical resource in urban environments that regulates bird community composition.
Key words: urban, nesting success, birds, community composition