Key Concepts of Bird Territorial Behavior
- Fixed Kernel Technique: An Internet technique for estimating the utilization of territories using an imaginary grid of points.
- Distance Measurement: The computer measures distances from all locations to the grid points to develop utilization contours.
- Utilization Contours: Represent areas where a specified percentage (e.g., 5%, 10%, 15%, and 95%) of locations occur, with the 95% contour often used as an estimate of home range.
- Home Range vs. Territory: Home range incorporates all locations (including foraging) while territory relates specifically to areas defended (e.g., singing locations).
- Research Method: Involved tracking birds with transmitters, observing their behavior, and conducting vegetation analysis, as opposed to older flush techniques.
- Findings on Territory Size: Previous beliefs that male songbirds defended territories of 1-2 hectares were challenged; a study found Swainson's warblers had territories averaging 6.7 hectares, showing exclusive use with minimal overlap (11%).
- Resource Defense: Territorial behavior arises from the need to defend resources essential for mating and survival (e.g., nesting sites, food).
- Costs of Territorial Behavior: Defending territories incurs energy costs, risk from predators, and can lead to injuries.
- Types of Territoriality: Differentiated into breeding territories and non-breeding territories, with some birds maintaining territories throughout the year.
- Territory Size and Bird Size: Larger birds typically maintain larger territories due to resource requirements.
- Environmental Influence: Fluctuating territory sizes in relation to availability of prey exemplified by the pomeranzeager's adaptation to lemming population cycles.
