Reed College Canyon

Birdwatching in the Reed Canyon: An Empirical and Theoretical Approach

author: Emile Schoffelen
advisor: David DeSante
year: 1977

ABSTRACT: This study attempts to segregate factors important in structuring the avian community of the Reed canyon. Census data collected over three seasons showed that species diversity was significantly lower in summer than in winter although total abundance remained constant. This surprising result is discussed in conjunction with the fact that the niche breadth and niche overlap of a dominant, generalist species, the Song Sparrow, as well as the community niche overlap, significantly increased from winter to summer for several niche dimensions. It is suggested that the breeding bird community of the Reed canyon may not be structured by competition. A combination of a high rate of winter survival of resident generalist species, heavy nest predation and the small size of the canyon is suggested as an alternative structuring force. It is concluded that equilibrium theories of ecology may not apply to man-altered environments.