PARENT SESSION
Wednesday, August 9, 1:30-5:00 pm
Symposium 14 - The urban food web: how humans alter the state and interactions of trophic dynamics
Cotton Row, Mezzanine Level, Cook Convention Center
Organized by: PS Warren (pswarren@forwild.umass.edu), C Tripler, C Lepczyk, and J Walker

This symposium addresses the unification of food web theory, with its classic debates over the regulation of populations and communities, and the inventive new approaches by which urban ecologists examine the dynamics of coupled social-biophysical systems.

For the birds-a comparison of human activities related to avian food webs between Phoenix, Arizona and southeastern Michigan.

Lepczyk, Christopher^{*,1, 2}, Warren, Paige^{3, 4}, Machabée, Louis⁴, Kinzig, Ann^{4, 5}, ¹ University of Wisconsin, Madison, Madison, WI² University of Wisconsin, Milwaukee, Milwaukee, WI³ University of Massachusetts, Amherst, MA⁴ Global Institute of Sustainability, Tempe, AZ, USA⁵ Arizona State University, Tempe, AZ

ABSTRACT- Numerous public and private organizations encourage people to manage their property in ways that are beneficial to wildlife, plants, and the larger ecosystem. As a result, people often engage in activities on their property that can directly or indirectly influence food webs. Such activities include gardening to attract birds and butterflies, installing ponds or bird baths, keeping pets indoors, and perhaps most commonly, feeding birds. In order to begin addressing how people influence food webs in urban areas we sought to assess how often and in what ways people elect to participate in activities intended to benefit birds. In parallel studies in Phoenix, Arizona and southeastern Michigan, we surveyed human behaviors related to bird feeding, planting vegetation, and allowing cats outdoors using mail surveys. We found both striking similarities and differences between the two regions. In both regions, a large proportion of respondents fed birds: 66% in southeastern Michigan and 47% in Phoenix, Arizona. The predominant food types were commercial seed mixtures, specialized seed (sunflower, thistle), or nectar. In Michigan, 80% of respondents engaged in at least one of three activities that influence avian food webs compared to 65% of respondents in Phoenix. Socioeconomic factors also corresponded to the activities, and hence food web, as illustrated by the relationship between providing sugar water (which attracts nectivores) and income level in Phoenix. Both regions highlight how human activities may be altering the urban food web and demonstrate the importance of using a social survey approach towards understanding ecological questions.

Key words: urban birds, human dimensions, social surveys