Red-throated Diver vs White-billed Diver

The Red-throated Diver (Gavia stellata) and White-billed Diver (Gavia adamsii) can be distinguished by bill color and size. The Red-throated Diver is smaller with a slender, dark bill, while the White-billed Diver is larger with a distinctive pale, yellowish bill. Both species share similar habitats but have different foraging behaviors.

1. Bill Color: Look for the pale, yellowish bill of the White-billed Diver compared to the slender, dark bill of the Red-throated Diver. 2. Size: Note the larger size of the White-billed Diver. 3. Throat Patch: In breeding season, the Red-throated Diver has a red throat patch. 4. Habitat: Observe the size and type of water body; White-billed Divers prefer larger lakes. 5. Behavior: Watch for foraging behavior; Red-throated Divers often fly to feed elsewhere.

The Red-throated Diver is the smallest loon species, whereas the White-billed Diver is larger and more robust.

The Red-throated Diver has a plain gray plumage with a distinctive red throat patch during breeding. The White-billed Diver has a more contrasting black and white plumage with a white face and neck during breeding.

Red-throated Divers are central-place foragers, flying between breeding and foraging areas. White-billed Divers are strongly territorial, defending their breeding lakes.

Both species breed in tundra regions, but the Red-throated Diver uses smaller, often coastal tundra ponds, while the White-billed Diver prefers larger lakes and slow-moving rivers.

The Red-throated Diver's call is described as cacophonous, while the White-billed Diver's vocalizations are less well-documented but include a variety of calls during breeding.