Habitat Selection Under Predation Hazard: Test of a Model with Foraging Minnows

Area of Science:

• Behavioral Ecology
• Foraging Theory
• Predator-Prey Dynamics

Background:

• Animals often face a trade-off between foraging rewards and predation risk.
• Predicting shifts between safe/low-reward and hazardous/high-reward habitats is crucial for understanding animal behavior.

Purpose of the Study:

• To present and test a model predicting habitat selection based on minimizing mortality risk while achieving a net energy gain.
• To determine the specific conditions under which a forager will switch from a safer to a more hazardous foraging area.

Main Methods:

• Developed a model where foragers minimize the ratio of mortality rate (μ) to gross foraging rate (f) (μ/f).
• Tested the model with juvenile creek chubs in an experimental stream with a refuge and two foraging sites varying in resource density and predator presence.
• Independently measured mortality hazard and foraging rates to predict habitat shifts.

Main Results:

• The model's prediction, "minimize μ/f," accurately described the creek chubs' habitat choices.
• Foraging preferences aligned with theoretical predictions regarding the resource level that would induce a shift to a more hazardous site.

Conclusions:

• The "minimize μ/f" rule provides a viable alternative to maximizing energy intake rate (f) when predation risk varies.
• This finding offers a simple, predictive framework for understanding habitat selection under predation risk.