Head to head
Great Crested Grebe vs Common Loon
Grebes and loons, which are called divers in Europe, are both foot-propelled diving birds that ride low in the water and chase fish beneath the surface, and both have legs set so far back that they can barely walk on land. They look similar enough to confuse, but they are not related, and they differ in size, feet, voice, and where they nest.
| Great Crested Grebe | Common Loon | |
|---|---|---|
| Family | Podicipedidae (grebes) | Gaviidae (loons or divers) |
| Size | Slender, medium-sized | Larger and heavier |
| Feet | Lobed toes, not fully webbed | Fully webbed |
| Bill and face | Thin dagger bill; crest and chestnut ruff when breeding | Thick bill; black head and chequered back when breeding |
| Voice | Growling and barking notes | Wild yodelling and wailing calls |
| Where it breeds | Reed-fringed lakes and reservoirs, widespread | Quiet northern wilderness lakes |
| Taking off | A short scrabble across the water | A long runway across open water |
| Shared quirk | Carries striped chicks on its back | Carries striped chicks on its back |
Grebe vs Loon: common questions
Are a grebe and a loon the same kind of bird?
No. They look and live alike but they are not close relatives, and their resemblance is a case of convergent evolution, two separate lineages independently becoming specialised foot-propelled diving birds. Loons are an ancient group with a fossil record going back tens of millions of years, and their nearest relatives are thought to be among the tubenoses and penguins. Grebes are a separate family whose closest living relatives, remarkably, appear to be the flamingos. The shared features, the streamlined body, the rear-set legs, the dagger bill, the habit of diving from the surface and carrying chicks on the back, all follow from the same way of making a living rather than from common ancestry.
Why do loons and grebes struggle to walk on land?
Because their legs are placed at the very back of the body, which is superb for diving and terrible for walking. Having the propulsion right at the stern lets the bird drive itself forward underwater with powerful strokes, steering with the feet like a boat's rudder and propeller combined. The cost is that on land the bird cannot balance or take proper steps, and it either shuffles awkwardly on its belly or stands almost upright and pushes itself along in a clumsy waddle. For this reason both grebes and loons come ashore only to nest, building the nest right at the water's edge or as a floating platform anchored to vegetation, so they never have to travel far on their feet.
What is that eerie wailing call on northern lakes?
That is a loon. The common loon has a repertoire of four main calls, and two of them are famous. The wail is a long, rising and falling, almost human cry used to keep in contact with a mate or chicks across a lake, and it is the sound most often used in films to signal a remote northern setting. The tremolo is a wavering, laughing call given in alarm or excitement, sometimes in flight. Males also give a yodel, a rising, repeated territorial call unique to each individual. Grebes, by contrast, make lower growling, barking, and clicking sounds that carry less far and are far less haunting, so a wild wailing cry drifting across a wilderness lake at dusk is almost always a loon.