University of Kansas Publications, Museum of Natural History Editors: E. Raymond Hall, Chairman, Theodore H. Eaton, Jr., Henry S. Fitch Volume 12, No. 5, pp. 241-296, 6 figs. Published March 7, 1962 University of Kansas Lawrence, Kansas

Fall Departure

Foraging and Food Habits

Bathing

Flight Song

Daily Frequency of Song

Types of Vocalizations

Table 1. Representative Singing Rates of Breeding Bell Vireos. All Rates Were at Air Temperatures Less Than 86° F. Each Instance Represents Approximately 30 Minutes of Observation.

Size of Territories

Permanence of Territories

Table 2. Size of the Nine Original Territories Occupied in 1960.

Maintenance of Territory

Table 3. Intraspecific Disputes in Maintenance of Territory.

Behavior

Aggressive Behavior of the Female

Interspecific Relationships

Table 4. Interspecific Conflict Observed in 1959 and 1960.

Discussion

Discussion

Building

Gathering of Nesting Material

Length and Hours of Nestbuilding

Abortive Nestbuilding Efforts

Renesting

The Nest

Table 6. Abortive Nesting Attempts in May and June of 1960.

Table 7. Dimensions of Nests in May (1960) and June (1960).

Clutch-size

Table 8. Average Numbers of Eggs per Nest (Number of Records in Parentheses)[F].

Incubation

The Roles of the Sexes in Incubation

Relief of Partners in Incubation

Development of the Nestlings

Table 9. Maturation of Nestling Bell Vireos. The First Day That an Activity Was Observed Is Shown.

Parental Behavior

Feeding of the Nestlings

Table 10. Feeding of the Nestlings.

Nest Sanitation

Fledging

Nest Parasites

Table 11. Egg Mortality in Bell Vireos.

Predation

Cowbird Parasitism

Table 12. Incidence of Cowbird Parasitism of the Bell Vireo Compared With Other Passerines in the Study Area in 1959 and 1960.