BirdNote Daily Birds Move from Fresh to Salt Water
Dec 24, 2025
Discover how Common Loons transition from tranquil freshwater lakes in summer to bustling saltwater bays in winter. Learn about their unique adaptations, including specialized salt glands that excrete excess salt, enabling them to thrive in varying environments. Uncover the energy strategies behind their nesting choices, as breeding adults prefer freshwater to conserve strength for raising chicks. Join in on a fascinating journey of seasonal migration and the resilience of these remarkable water birds!
AI Snips
Chapters
Transcript
Episode notes
Seasonal Freshwater-To-Saltwater Migration
- Many waterbirds, like the Common Loon, migrate from freshwater breeding lakes to salty winter bays each year.
- This shift relies on physiological adaptations that allow them to survive high salt intake.
Salt Glands Remove Excess Salt
- Loons ingest salt with prey in marine waters, which raises blood salt levels and triggers a physiological response.
- Specialized salt glands above the eyes excrete excess salt through ducts to the nostrils, returning it to the environment.
Energetic Cost Of Salt Gland Activation
- Activating salt glands consumes substantial calories, creating an energetic cost for living in saltwater.
- Breeding on freshwater may conserve energy for adults raising chicks by avoiding that metabolic expense.