Current Ornithology

1 Testosterone and Polygyny in Birds.- 1. Introduction.- 2. Types of Polygyny and Associated Testosterone Profiles.- 3. Testosterone Levels and Breeding Ecology, Age, and Reproductive Success.- 4. Testosterone, Male-Male Aggression, and Parental Care.- 5. Testosterone Levels and Social Interactions.- 6. Costs of High Testosterone Levels.- 7. Conclusions.- 8. Summary.- References.- 2 Using Migration Counts to Monitor Landbird Populations: Review and Evaluation of Current Status.- 1. Introduction.- 2. What is a “Migration Count”?.- 3. Collection of Migration Count Data.- 4. Analysis of Migration Count Data.- 5. Evaluation of Migration Counts for Population Monitoring.- 6. Synthesis: The Pros and Cons of Using Migration Counts for Population Monitoring.- 7. The Future of Migration Monitoring in North America.- References.- 3 Ptilochronology: A Review and Prospectus.- 1. Introduction.- 2. Causes of Growth Bars.- 3. Ubiquity of Growth Bars.- 4. One Growth Bar Denotes 24 Hours of Feather Growth.- 5. Growth Bar Width is Sensitive to Nutritional Condition.- 6. Other Possible Factors Controlling Growth Bar Width.- 7. Applications.- 8. Prospectus.- References.- 4 Individual Voice Discrimination in Birds.- 1. Introduction.- 2. Neighbor-Stranger Recognition and Evidence for Individual Recognition by Song.- 3. Processes of Individual Recognition.- 4. How to Distinguish among Processes of Individual Recognition.- 5. Design and Execution of Experiments Testing Individual “Voice” Recognition in the Field.- 6. The Potential Significance of Individual “Voice” Recognition.- 7. Signature Adaptations and Perceptual Adaptations for Individual Recognition.- 8. Concluding Remarks.- 9. Summary.- References.- 5 The Evolution Of Bird Coloration And Plumage Elaboration: A Review ofHypotheses.- 1. Introduction.- 2. The Hypotheses.- 3. Future Directions for the Study of Animal Coloration.- 4. Conclusions.- References.- 6 Hatching Asynchrony And The Onset Of Incubation In Birds, Revisited: When Is The Critical Period?.- 1. Introduction.- 2. The Onset of Incubation as the Principal Proximate Cause of Hatching Patterns.- 3. Hatching Patterns in Birds.- 4. Hypotheses for the Evolution of Hatching Asynchrony.- 5. Findings from Experimental Tests.- 6. Synthesis: Integrating Multiple Hypotheses through Modeling.- 7. Conclusions.- 8. Summary.- References.