Optimal Foraging Theory: Part 1 — The Logic of Foraging Decisions

Vocabulary flashcards covering the core concepts, models, empirical tests, and Tinbergen frameworks of Optimal Foraging Theory.

Optimal Foraging Theory (OFT)

A theoretical framework proposing that natural selection shapes behavioral decision rules to maximize a fitness currency (typically net energy gain rate), subject to real constraints.

Currency

The variable that natural selection is assumed to maximize in a foraging model, most commonly net energy gain rate, or occasionally survival probability.

Foraging Constraints

Factors that restrict a predator's options and performance, including handling time, digestion, predation risk, and incomplete information.

Profitability

The ratio of an item's energy content to its handling time, calculated as $E \div h$, where $E$ is energy content and $h$ is handling time.

Handling Time ($h$)

The time spent pursuing, subduing, and consuming a single prey item.

Optimal Diet Model

A model assuming prey are met sequentially, where prey types are ranked by profitability and a type is added to the diet only if doing so raises the long-term energy intake rate.

Zero-One Rule

The principle that a lower-ranked prey item is either always eaten or completely ignored, determined entirely by the encounter rate with higher-ranked prey rather than the abundance of the lower-ranked prey.

Proximate Causation

An explanation of behavior focused on immediate internal factors operating over a lifetime, specifically physiological mechanisms and developmental ontogeny.

Ultimate Causation

An explanation of behavior focused on evolutionary time, specifically how a behavior affects fitness (survival value) and how it evolved across phylogenetic lineages.

Tinbergen's Four Questions

A framework categorizing biological inquiries into proximate causes (Mechanism: physiological causation; Development: emergence over lifespan) and ultimate causes (Survival: fitness effects; Phylogeny: evolution across lineages).

Krebs et al. (1977) Experiment

A conveyor-belt study feeding great tits large and small mealworm pieces, verifying that birds show an abrupt zero-one switch to ignoring low-profit prey above a threshold encounter rate of high-profit prey.

Zach (1978, 1979) Shell-Dropping Study

A study demonstrating that Northwestern crows (Corvus caurinus) minimize total flight effort (drop height multiplied by expected drops) by dropping large whelks from an observed mean height of $5.2\,\text{m}$ (predicted optimum $\approx 5\,\text{m}$).

Johnstone & Norris (2000) Oystercatcher Study

Research showing Eurasian Oystercatchers selectively consume mid-sized mussels, a pattern accurately predicted by modeling bill constraints, opening time, and failed-attempt times for hammerers and stabbers.