Red Crested Pochard - male |
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)
No comments:
Post a Comment