Dipper

Walking underwater

The dipper is the only member of the songbird order capable of truly walking underwater. To feed on insect larvae, freshwater shrimps, and small fish on the streambed, it enters the current, uses its wings as hydrofoils to resist the downstream push, and walks along the bottom with its feet. It can stay submerged for 30+ seconds.

Dippers have several adaptations for this:

• Dense waterproof plumage — highly oiled and resistant to wetting
• Nictitating membrane — transparent third eyelid that protects eyes underwater
• Large oil gland — produces more preening oil than any other passerine
• High haemoglobin in blood — stores more oxygen for submersion

The dipping motion

The name comes from the bird’s incessant bobbing — a constant, rapid up-down dipping of the whole body while perched on rocks. The function is debated; it may improve vision into water by reducing surface glare through movement, or it may be a recognition signal between individuals.

Winter singing

Dippers are remarkable for singing through winter, including during heavy frost and snow. The male’s rich, bubbling song carries over the sound of the river. In Britain, the dipper’s song in January and February on a clear mountain stream is one of the most distinctive and refreshing wildlife experiences available.

Water quality indicator

Dippers require clean, fast-flowing water with high invertebrate diversity. Their absence from a river system is a reliable indicator of water quality problems (acidification, sediment, pollution). Their presence indicates an ecologically healthy upland river.