How animals distribute themselves in space: variable energy landscapes

Area of Science:

• Animal behavior
• Ecology
• Bioenergetics

Background:

• Foraging efficiency is critical for animal fitness, influencing brood-rearing, body condition, and predator avoidance.
• Energetic costs of movement, derived from habitat features and variable conditions, can be mapped into "energy landscapes."
• This study focused on energy landscapes in Gentoo Penguins (Pygoscelis papua) at two colonies in the Falkland/Malvinas Islands.

Purpose of the Study:

• To investigate and characterize the energy landscapes utilized by Gentoo Penguins.
• To understand how variations in energy landscapes influence foraging behavior and breeding success.
• To explore the relationship between energy gain, foraging costs, and fitness outcomes.

Main Methods:

• Utilized accelerometers and GPS loggers to track penguin movements and habitat use.
• Analyzed dive parameters (depth, pelagic vs. benthic) and correlated them with energy expenditure.
• Assessed food availability using carbon and nitrogen stable isotope values and isotopic niche metrics.

Main Results:

• Marine areas used by penguins, dive patterns, and proportions of dive types varied significantly between years and colonies.
• Energy landscapes differed annually, correlating with changes in food availability, as indicated by isotopic data.
• The second year featured lower foraging costs per energy gain, coinciding with higher breeding success.

Conclusions:

• Energy landscapes are dynamic and vary over time, influencing seabird foraging decisions.
• Penguins actively select foraging areas within energy landscapes that minimize energetic costs.
• Energy landscapes effectively link energy gain, variable foraging costs, and breeding success, supporting their role in animal foraging behavior.