Friday, 2 December 2016

Spain 1: Red-Crested Pochard

Red Crested Pochard - male
 Although we saw several species of duck on the trip, one of my favourites is one of the showiest of Eurasian ducks, the Red-Crested Pochard. I have seen them many times before, but they are always a good bird to find. Males and females are quite distinct, with only males displaying the bright orange head that gives them their name.

Red-Crested Pochard - female
Red-Crested are sufficiently different from other pochards (Aythya spp) to be placed in its own genus, Netta. Although now with only a single species the recently extinct Pink-Eared Duck has been found to be a close relative and may belong in the same genus.

Pink-Headed Duck - 1847 illustration
Red-Crested Pochards are on the large size for ducks, reaching well over 1kg and 50cm long, and many populations are migratory, especially towards the eastern end of their range, which is most of continental Europe eastwards to north west China. In southwest Europe they are mostly resident, but disperse after the spring breeding season. Wintering grounds are around the Mediterranean and across to India and south east Asia. Between completing breeding and travelling to the wintering grounds they may make long journeys to suitable safe lakes where they undergo a complete moult and replacement of their flight feathers, during which time they are flightless and vulnerable.

All pochards are referred to as diving ducks as a result of their habit of feeding from water plants several meters down. This contrasts with dabbling ducks such as Mallards, which feed on or near the water surface. For plants to grow at depth the water must be clear, and eutrophication as a result of agricultural run-off can make an otherwise suitable water body unusable, especially for breeding.

Red-Crested Pochards build their nest on the ground, preferably amongst reeds fringing the lake. Clutch size is usually 8-10, with the eggs being pale green. They hatch after 26-28 days incubation, which is solely by the female as with most species of duck. The male tends to guard the female – probably against rival males rather than predators – until shortly before hatching, then leaves the fermale to raise the young on her own. The ducklings feed on both water plants and aquatic invertebrates, fledging at around 10 weeks.

As a result of their vast range and adaptable diet, RC Pochards are currently classed as Least Concern by the IUCN, although there may have been some local extinctions from land use changes. On the other hand, their vivid colours and ease of husbandry and breeding in captivity means that there are also many escapes from waterfowl collections. This is a particular problem in England, where a RC Pochard may be a vagrant from the nearest breeding population across the North Sea, an escape from a local collection or private owner, or part of a feral breeding population – this last is especially acute in the south and east of England.

(Images from Wikipedia)

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