Birds
Great Crested Grebe
Podiceps cristatus · also called crested grebe
The great crested grebe is the elegant, long-necked diving bird you see sitting low on an open lake, and in spring it puts on one of the great performances of the bird world — a pair rising chest to chest out of the water, weed dangling from their bills, paddling furiously in a mirrored dance. A century and a half ago the same bird was almost shot out of Britain for its feathers.
Overview
Podiceps cristatus is a slender diving waterbird, about 46 to 51 cm long, that sits low in the water with a white neck, a dagger bill, and, in the breeding season, a black double crest and a fannable chestnut-and-black face ruff. In winter the head is plain. It lives on open fresh water across Europe, Asia, Africa, and Australasia, and it dives for fish in underwater pursuit.
The dance, and the chicks
Its courtship is elaborate and mutual, including head-shaking with the ruff spread and the famous weed ceremony, and it was one of the first bird displays to be studied scientifically. The striped chicks ride on a parent’s back, tucked under the wings, and a parent will dive with them still aboard.
Odd habits
Grebes swallow their own feathers and feed them to their young, forming a stomach plug that seems to protect the gut from sharp fish bones. Their legs are set so far back that they can barely walk, so they build a floating nest anchored to reeds and almost never come ashore.
Status
The great crested grebe is Least Concern. The British population crashed to about 50 pairs by 1860 through the trade in “grebe fur” for hats, and the outcry helped found the RSPB. Protected and helped by new gravel pits and reservoirs, it has recovered strongly.
Great Crested Grebe: common questions
Why is the great crested grebe famous for its courtship?
Because its displays are unusually elaborate, mutual, and easy to watch on open water. The naturalist Julian Huxley studied them in 1914 and his account became a landmark in the science of animal behaviour. The best known ceremony is the weed dance, in which both members of a pair dive, collect trailing waterweed in their bills, then surface and rear up breast to breast, paddling hard to stay vertical while shaking their heads with the weed held out like an offering. There are also head-shaking displays with the crest and ruff fanned, a cat display in which a bird hunches with wings raised, and a discovery ceremony where one bird rises from a dive in front of its mate. Both sexes perform, and the displays strengthen the pair bond rather than one sex simply courting the other.
Why do grebes carry their chicks on their backs?
It keeps the young warm, safe from underwater predators such as large fish and pike, and out of cold water that would quickly chill their small bodies. For the first few weeks after hatching, great crested grebe chicks spend much of their time riding between the wings on a parent's back, and the adult can swim, feed, and even dive while carrying them, with the chicks gripping the feathers and disappearing beneath the water for a moment before bobbing back up as the parent surfaces. The parents take turns, one carrying the brood while the other dives for fish to feed them. The striking black-and-white head stripes of the chicks may help the parents keep track of them.
Do great crested grebes really eat feathers?
Yes, and it is a normal, deliberate habit rather than an accident. Adult grebes pluck and swallow small soft feathers from their own flanks and belly, sometimes dozens at a time, and they also feed feathers to their chicks from the first days of life. The feathers collect in the stomach as a dense mat. The leading explanation is that this plug cushions and traps the many sharp fish bones a grebe ingests, holding them in the stomach until they are digested or worked into a pellet that the bird coughs up, rather than letting them pass into and pierce the intestine. All grebe species do this.
How did the great crested grebe nearly go extinct in Britain?
Through the Victorian fashion trade. The grebe's breast and belly are covered in an exceptionally dense, silky, waterproof layer of feathers that was marketed as grebe fur or tippet and used to trim hats, capes, and muffs and to make ladies' stoles. Birds were shot in large numbers at their breeding lakes, and by 1860 the British breeding population had fallen to roughly 50 pairs. Public revulsion at the slaughter of birds for millinery helped drive the campaign that produced early bird-protection laws and the founding of the Society for the Protection of Birds, later the RSPB, in 1889. Protected, and helped by the spread of gravel pits and reservoirs, the grebe recovered strongly and is now a common sight on open water across Britain.