Grebes and dabchicks (collectively known as grebes) form the ancient order Podicipediformes. These freshwater diving birds have separate web-like lobes on each toe. Their legs are set far back – efficient for swimming underwater but awkward for walking on land, which the birds avoid. They feed, sleep and build their nests on water.
Grebes’ nests can be swamped by wash from boats or by changing water levels on hydro lakes. They can be killed by dogs, stoats and other swimming predators.
Australasian crested grebe – kāmana
The Australasian crested grebe or kāmana (Podiceps cristatus australis) has a long, sinuous neck with a red-orange ruff. Its elegant head tapers to a long pointed bill. The bird’s black head-crest is known to Māori as tikitiki – also meaning the topknots worn by men of rank. Adults are about 50 centimetres long and weigh 1.1 kilograms.
Crested grebes chase fish underwater, and also take crustaceans and insects. They can dive for up to a minute.
In crested grebes’ courtship displays, they float facing each other, fanning their wings and fluffing up their head crests and neck ruffs. At the height of the display they rear upwards until almost vertical, breast to breast and bill to bill, crooning and gurgling.
A Māori tradition recounts that kāmana (crested grebes) dive down to lay their eggs and raise their chicks on the bed of Rotopounamu, a green volcanic lake.
They build floating nests, often anchored to reeds or other plants. Their three or more white eggs soon become brown, stained by the wet vegetation with which adults cover the nest when leaving to feed. Grebes carry their chicks on their backs as they swim. They feed them on fish, and give them downy feathers to swallow as protection from sharp fish bones.
Distribution and population
A subspecies of the great crested grebe of Europe, Asia and Africa, the Australasian crested grebe is found in Australia and New Zealand. Gone from the North Island, it now lives mainly on small subalpine lakes in Canterbury and Otago, on lakes in Fiordland and Westland and lowland lakes in Canterbury. Grebes need lakes with vegetation in the shallows for cover and shelter.
In winter some crested grebes move to coastal wetlands, especially Lake Forsyth (Wairewa) on Banks Peninsula and nearby Lake Ellesmere (Te Waihora), where they have recently begun breeding. Although they have small wings, they occasionally fly long distances – mostly at night.
Crested grebes were endangered in New Zealand. In 2004, there were 350 adult birds in New Zealand. Nearly half lived on just two lakes – Lake Heron in inland Canterbury, and Lake Hayes, near Queenstown. But in 2007, numbers had started increasing thanks to predator control.
New Zealand dabchick – weiweia
The small endemic dabchick (Poliocephalus rufopectus) has a total population of about 1,700 birds, scattered around the North Island and just a few South Island lakes. The bird is shy and secretive. Like other grebes, it builds a floating nest, anchored to reeds or overhanging branches.
The New Zealand dabchick is about 29 centimetres long and weighs 250 grams. Its head is streaked with fine silver feathers.
If disturbed, dabchicks either skitter rapidly across the water, or sink, leaving just the head exposed.
New Zealand dabchicks lack the flamboyant crests and neck ruffs of crested grebes – hence the Māori expression ‘he tangata weiweia’ (a dabchick man), meaning a person of lowly standing.
Foods include aquatic insects and larvae such as waterboatmen and dragonflies, and freshwater snails, crayfish and small fish. Dabchicks search for food underwater, sometimes starting their dive with a forward leap. They also feed on the surface, dipping their head underwater and sweeping it from side to side. They sometimes snatch flying insects.
Australasian little grebe
The Australasian little grebe (Tachybaptus novaehollandiae) is about 25 centimetres long and weighs 220 grams. Although these grebes seldom fly, they reached New Zealand from Australia in the 1960s, and are a rare self-introduced native. In 2005 there were around 100 birds on sheltered lakes and farm ponds around New Zealand, mainly north of Auckland.