Prey availability and foraging activity by tundra-nesting sea ducks: Strong preference for specific wetland types

Area of Science:

• Ecology
• Ornithology
• Climate Change Science

Background:

• Arctic tundra wetlands are vital breeding grounds for waterbirds.
• Different wetland types vary in characteristics and vulnerability to climate change.
• Understanding wetland use by sea ducks is crucial for conservation.

Purpose of the Study:

• To investigate the availability and use of diverse wetland types by four sea duck species (Mergini) on Alaska's Arctic Coastal Plain.
• To determine factors influencing sea duck wetland selection, including vegetation and invertebrate availability.
• To assess the vulnerability of preferred wetland types to climate warming.

Main Methods:

• Studied prelaying female sea ducks (long-tailed ducks, Steller's, spectacled, and king eiders).
• Assessed wetland characteristics (area, depth, vegetation) and invertebrate biomass density.
• Analyzed sea duck occurrence and feeding behavior across different wetland types.

Main Results:

• All four sea duck species showed a strong preference for shallow, vegetated wetlands over deeper lakes.
• Wetland selection was not directly correlated with invertebrate biomass density.
• Sea ducks strongly preferred *Arctophila fulva* dominated wetlands over *Carex aquatilis* wetlands, despite lower invertebrate biomass in the former.
• Prey accessibility in *Arctophila* vegetation likely explains this preference.

Conclusions:

• Shallow *Arctophila* wetlands are critical foraging habitats for Arctic sea ducks.
• These preferred wetlands have significantly decreased in number and area and are highly vulnerable to climate warming.
• Climate-driven changes in wetland availability may impact sea duck populations, contingent on their adaptive capacity.