James N. M. Smith teaches at the University of British Columbia in Vancouver. Terry L. Cook works for the Nature Conservancy in Seattle. Stephen I. Rothstein teaches at the University of California, Santa Barbara. Scott K. Robinson holds joint appointments at the Illinois Natural History Survey and the University of Illinois, Champaign. Spencer G. Sealy teaches at the University of Manitoba.

• Foreword: Cowbirds and Bull-hockey (Paul R. Ehrlich) General Introduction: Brown-headed Cowbirds as a Model System for Studies of Behavior, Ecology, Evolution, and Conservation Biology (James N. M. Smith and Stephen I. Rothstein) Part I. Population Trends of Cowbirds and Hosts and Relevant Methodology 1. Introduction (Stephen I. Rothstein and Scott K. Robinson) 2. Temporal and Geographic Patterns in Population Trends of Brown-headed Cowbirds (Bruce G. Peterjohn, John R. Sauer, and Sandra Schwarz) 3. Cowbird Population Changes and Their Relationship to Changes in Some Host Species (David A. Wiedenfeld) 4. The Spread of Shiny and Brown-headed Cowbirds into the Florida Region (Alexander Cruz, John W. Prather, William Post, and James W. Wiley) 5. Brown-headed Cowbird Population Trends at a Large Winter Roost in Southwest Louisiana, 1974-1992 (Brent Ortego) 6. An Evaluation of Point Counts and Playbacks as Techniques for Censusing Brown-headed Cowbirds (R. Kirk Miles and David A. Buehler) 7. The Structure and Function of Cowbird Vocalizations and the Use of Playbacks to Enhance Cowbird Detectability: Relations to Potential Censusing Biases (Stephen I. Rothstein, Chris Farmer, and Jared Verner) Part II. Cowbird Spacing Behavior, Host Selection, and Negative Consequences of Parasitism for Commonly Used Hosts 8. Introduction (James N. M. Smith, Spencer G. Sealy, and Terry L. Cook) 9. Spatial Patterns of Breeding Female Brown-headed Cowbirds on an Illinois Site (Arlo Raim) 10. Differences in Movements, Home Range, and Habitat Preferences of Female Brown-headed Cowbirds in Three Midwestern Landscapes (Frank R. Thompson III and William D. Dijak) 11. The Effects of Host Numbers on Cowbird Parasitism of Red-winged Blackbirds (Christy A. Carello and Gregory K. Snyder) 12. Cowbird Brood Parasitism on a Little-used Host: The Yellow-headed Blackbird (Alfred M. Dufty, Jr.) 13. Host Selection in the Forest Interior: Cowbirds Target Ground-nesting Species (D. Caldwell Hahn and Jeff S. Hatfield) 14. Reproductive Interactions between Brown-headed Cowbirds and Plumbeous Vireos in Colorado (Jameson F. Chace, Alexander Cruz, and Rebecca E. Marvil) 15. Effects of Multiple Parasitism on Cowbird and Wood Thrush Nesting Success (Cheryl L. Trine) 16. Comparing the Relative Effects of Brood Parasitism and Nest Predation on Seasonal Fecundity in Passerine Birds (Joseph A. Grzybowski and Craig M. Pease) Part III. Host-Cowbird Behavioral Interactions 17. Introduction (James N. M. Smith and Spencer G. Sealy) 18. Morning Nest Arrivals in Cowbird Hosts: Their Role in Aggression, Cowbird Recognition, and Host Response to Parasitism (Dirk E. Burhans) 19. Yellow Warbler Nest Attentiveness before Sunrise: Antiparasite Strategy or Onset of Incubation? (Spencer G. Sealy, D. Glen McMaster, Sharon A. Gill, and Diane L. Neudorf) 20. The Ecology of Egg-puncture Behavior by the Shiny Cowbird in Southwestern Puerto Rico (Tammie K. Nakamura and Alexander Cruz) 21. Why Do Female Brown-headed Cowbirds Remove Host Eggs? A Test of the Incubation Efficiency Hypothesis (Brian D. Peer and Eric K. Bollinger) Part IV. Environmental Correlates of Cowbird Parasitism at Multiple Spatial Scales 22. Introduction (Scott K. Robinson and James N. M. Smith) 23. The Role of Vegetation in Cowbird Parasitism of Yellow Warblers (William H. Howe and Fritz L. Knopf) 24. Association of Cowbird Parasitism and Vegetative Cover in Territories of Southwestern Willow Flycatchers (Jamie C. Uyehara and Mary J. Whitfield) 25. Interhabitat Differences in Parasitism Frequencies by Brown-headed Cowbirds in the Okanagan Valley, British Columbia (David Ward and James N. M. Smith) 26. Cowbird Parasitism and Nest Predation in Fragmented Grasslands of Southwestern Manitoba (Stephen K. Davis and Spencer G. Sealy) 27. Cowbird Parasitism in Grassland and Cropland in the Northern Great Plains (Rolf R. Koford, Bonnie S. Brwn, John T. Lokemoen, and Arnold D. Kruse) 28. Distribution and Habitat Associations of Brown-headed Cowbirds in the Green Mountains of Vermont (Daniel R. Coker and David E. Capen) 29. Impacts of Cowbird Parasitism on Wood Thrushes and Other Neotropical Migrants in Suburban Maryland Forests (Barbara A. Dowell, Jane E. Fallon, Chandler S. Robbins, Deanna K. Dawson, and Frederick W. Fallon) 30. Cowbird Distribution at Different Scales of Fragmentation: Trade-offs between Breeding and Feeding Opportunities (Therese M. Donovan, Frank R. Thompson III, and John R. Faaborg) 31. Brown-headed Cowbird Parasitism of Migratory Birds: Effects of Forest Area and Surrounding Landscape (Lisa J. Petit and Daniel R. Petit) 32. Biogeographic, Landscape, and Local Factors Affecting Cowbird Abundance and Host Parasitism Levels (Frank R. Thompson III, Scott K. Robinson, Therese M. Donovan, John R. Faaborg, Donald R. Whitehead, and David R. Larsen) 33. Cowbird Parasitism in a Fragmented Landscape: Effects of Tract Size, Habitat, and Abundance of Cowbirds and Hosts (Scott K. Robinson, Jeffrey P. Hoover, and James R. Herkert) 34. Within-landscape Variation in Patterns of Cowbird Parasitism in the Forests of South-central Indiana (Donald E. Winslow, Donald R. Whitehead, Carolyn Frazer Whyte, Matthew A. Koukal, Grant M. Greenberg, and Thomas B. Ford) 35. Effects of Land-use and Management Practices on the Presence of Brown-headed Cowbirds in the White Mountains of New Hampshire and Maine (Mariko Yamasaki, Toni M. McLellan, Richard M. DeGraaf and Christine A. Costello) Part V. Cowbird Management, Host Population Limitation, and Efforts to Save Endangered Species 36. Introduction (Stephen I. Rothstein and Terry L. Cook) 37. Brown-headed Cowbird Control on Kirtland's Warbler Nesting Areas in Michigan, 1972-1995 (Michael E. DeCapita) 38. Cowbird Control and the Endangered Least Bell's Vireo: A Management Success Story (John T. Griffith and Jane C. Griffith) 39. Cowbird Control Program at Fort Hood, Texas: Lessons for Mitigation of Cowbird Parasitism on a Landscape Scale (Timothy J. Hayden, David J. Tazik, Robert H. Melton, and John D. Cornelius) 40. Results of a Brown-headed Cowbird Control Program for the Southwestern Willow Flycatcher (Mary J. Whitfield) Contributors Index