Great Crested Grebes

The Southern Crested Grebe. Podiceps cristatus australis (Kaimana)

A rare, threatened and protected species in New Zealand the Southern crested grebe is now confined to the South Island with an estimated population of

Breeding is normally from September-February, though in Lake Wanaka birds have been recorded breeding in winter (eggs laid June 6th,18th and 21st). Clutch size is 3-5 eggs and incubation of 23-26 days commences immediately the first egg is laid, thus hatching is asynchronous leading to an age hierarchy within a brood, which in turn leads to a degree of sibling rivalry. Nests are abandoned once all eggs have hatched (though territories may be defended) and chicks are carried on the backs of parents for up to 3 weeks post hatching. Parental care continues for up-to 16-18 weeks. Birds may breed more than once during the breeding season.

A programme was initiated in Wanaka in 2013 to investigate the recorded very high mortality of eggs and chicks of Grebes observed in most of the South Island lakes and waterways. This has led to the design and close monitoring of artificial nest sites in the Roys Bay marina area. As of mid- February 2016, 109 chicks have been successfully hatched. From these observations it has been suggested that rapid lake level fluctuations (natural and manmade) combined with a shortage of suitable habitat are the most likely cause of low numbers of Grebes in New Zealand.

Grebes are renowned for their elaborate and beautiful courtship behaviour and this was deserving of the attention of Sir Julian Huxley who in the prologue to his early work on the grebe wrote-
“A good glass, a notebook, some patience and a spare fortnight in spring; with these I not only managed to discover many unknown facts about the great crested grebe, but also had one of the pleasantest of holidays- go thou and do likewise”.

Please Click to Download PDF of John Darby’s Recent Royal Society Talk