Richard T. Holmes¹ & James N.M. Smith²

1Department of Biological Sciences, 6044 Gilman, Dartmouth College, Hanover, New Hampshire 03755, USA, e-mail richard.t.holmes@dartmouth.edu; ²Department of Zoology, University of British Columbia, Vancouver, B.C. V6T 1Z4, Canada, e-mail smith@bcu.ubc.ca

Holmes, R.T. & Smith, J.N.M. 1999. Population limitation and regulation in passerine birds. In: Adams, N.J. & Slotow, R.H. (eds) Proc. 22 Int. Ornithol. Congr., Durban: 2932. Johannesburg: BirdLife South Africa.

How animal populations are limited or regulated remains one of the major questions in ecology, and studies of birds have contributed greatly to our current understanding of this topic. Passerine populations are affected by several limiting factors, and many appear to be regulated, yet the underlying mechanisms are still incompletely known. In this symposium, Sutherland examines the role of behaviour in population regulation and consequent conservation implications. In a related paper, Rodenhouse et al. consider a model in which environmentally caused heterogeneity among sites, in combination with pre-emptive site selection, can lead to regulation of population size. Arcese and Smith discuss a common mechanism limiting the sizes of bird populations: The effects of brood parasites and predators on reproductive success. They also consider how knowledge of the causes of nesting failure can be used for management and conservation purposes. Finally Dias et al. and Pulliam take a larger landscape-level view, and consider, respectively, the role of source sink dynamics in population regulation and the usefulness of spatially-explicit models in understanding the distribution and abundance of bird populations. These papers have the common thread that spatial processes at both local and regional scales are often critical to the understanding of avian population dynamics.