Citation
Golden-winged Sunbird Territorial Economics Studies
TL;DR
High-density resources (>100 flowers/acre) yield 33% surplus, vigorous defense
Empirical demonstration of resource-defense threshold with precise caloric accounting. Gill's tracking of 47 sunbirds over 3 years across different flower densities provided the quantitative evidence that organisms calculate territorial economics continuously.
The finding that sunbirds abandon territoriality entirely when resource density drops below threshold directly informs the chapter's argument that businesses should similarly recognize when territorial defense costs exceed value.
Key Findings from Gill (1978)
- High-density resources (>100 flowers/acre) yield 33% surplus, vigorous defense
- Medium-density (30-100/acre) yields 7% surplus, weak defense
- Low-density (<30/acre) makes defense impossible, nomadic strategy adopted
- Optimal strategy adapts to resource density, not fixed