The Lévy flight foraging hypothesis in a pelagic seabird

Area of Science:

• Ecology
• Animal Behavior
• Movement Ecology

Background:

• Lévy flight foraging models heavy-tailed movement patterns, complementing Brownian-based correlated random walks.
• The efficiency of foraging tactics depends on prey availability, with Lévy flights excelling in scarce conditions.
• Previous studies faced controversy due to statistical misapplication, but recent methods offer stronger evidence.

Purpose of the Study:

• To investigate Lévy flight foraging compliance in Cory's shearwaters using advanced statistical techniques.
• To analyze movement patterns, including turning angles and move lengths, of foraging seabirds.
• To determine the influence of ecological constraints on search strategy selection.

Main Methods:

• Utilized maximum-likelihood and Bayesian methods to analyze 77 GPS-tracked foraging trajectories.
• Examined both turning angles and move length distributions to assess foraging patterns.
• Tracked Cory's shearwaters (Calonectris diomedea diomedea) in Mediterranean colonies during incubation and chick rearing.

Main Results:

• Correlated random walk fitted 6 trajectories; adaptive correlated random walks fitted 32.
• Lévy flight patterns were observed in 36 trajectories, indicating this search strategy.
• Lévy flights were more probable during chick provisioning, suggesting adaptation to resource scarcity.

Conclusions:

• Lévy flight foraging is a relevant framework for understanding Cory's shearwater search tactics.
• Foraging strategy selection is dynamically linked to biological and ecological constraints.
• This study provides robust evidence for Lévy flight behavior in this pelagic bird species.