The Starling's Algorithm

RIM held onto BlackBerry enterprise customers while smartphone margins evaporated. Their US market share dropped from 43% in 2010 to under 5% by 2012—yet leadership remained convinced their "loyal corporate user base would sustain them." They pecked at empty branches. Starlings would have flown to better bushes six quarters earlier.

Eric Charnov's 1976 Marginal Value Theorem describes how starlings (and all optimal foragers) decide when to leave berry bushes: stay while (next berry value × finding probability) > (travel cost + opportunity cost of alternatives). The math is elegant. The behavior is universal. Kacelnik's 1984 experiments confirmed that starlings optimize load size based on travel distance—they never exhaust patches, they exit when marginal return drops below expected return from moving.

This framework applies foraging optimization to customer, market, and product exit decisions. Harvard Business School research shows 15-20% of customers generate 100%+ of profits, while 10% are deeply unprofitable. Most companies hold assets too long. They milk declining customers, defend shrinking markets, maintain dying products—all because exit feels like failure. Starlings don't moralize about leaving bushes. They calculate.

Step 1: Calculate marginal value of continued engagement. For a customer: (Next deal revenue × Margin × Retention probability) - (Sales cost + Delivery cost). Step 2: Calculate opportunity cost—expected profit from the next-best alternative use of that sales capacity. Step 3: Exit when marginal value drops below opportunity cost.

The framework dissolves sunk cost fallacy through biological reframing. Starlings invested time finding the bush—they leave anyway. For the full Foraging Optimization chapter with portfolio exit strategies, see Resource Dynamics.