Red-crested pochard

Netta rufina

Krooneend / Kolbenente / Nette rousse

The red-crested pochard is a large diving duck. Its breeding habitat is lowland marshes and lakes in southern Europe and Central Asia, wintering in the Indian Subcontinent and Africa. It is somewhat migratory, and northern birds winter further south into north Africa. The adult male is unmistakable. It has a rounded orange head, red bill and black breast. The flanks are white, the back brown, and the tail black. The female is mainly a pale brown, with a darker back and crown and a whitish face. Eclipse males are like females but with red bills. They are gregarious birds, forming large flocks in winter, often mixed with other diving ducks, such as common pochards. They feed mainly by diving or dabbling. They eat aquatic plants, and typically upend for food more than most diving ducks.

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern (IUCN, 2012).

The species is fully migratory (Snow and Perrins 1998) or locally dispersive (e.g. in Europe) (del Hoyo et al. 1992) and breeds from mid-April to early-June (Madge and Burn 1988) in single pairs or loose groups (del Hoyo et al. 1992). Males and non-breeders moult and become flightless for four weeks between June and August (females moulting one month later) (Scott and Rose 1996) prior to which they may make extensive moult migrations which take them considerable distances from the breeding waters (Madge and Burn 1988). Once this post-breeding moult is complete the species departs for its winter quarters, arriving there from October onwards (Madge and Burn 1988). The species is highly gregarious for most of the year (Snow and Perrins 1998) and although it is more commonly found in small groups (Madge and Burn 1988) it often forms large concentrations (Madge and Burn 1988, Scott and Rose 1996) of several hundred individuals (Scott and Rose 1996) in moulting and wintering areas (Madge and Burn 1988). It feeds diurnally, being most active during the early morning and evening (Kear2005b). 

The species inhabits inland deep fresh or brackish (del Hoyo et al.1992) reed-fringed lakes, rivers, or saline and alkaline lagoons (Kear2005b) in open country (del Hoyo et al. 1992), also occurring (less often) on estuaries, river deltas and other sheltered coastal habitats (del Hoyo et al. 1992) on passage (Madge and Burn 1988) or during the winter (Scott and Rose 1996). 

The diet of this species consists predominantly of the roots, seeds and vegetative parts of aquatic plants (Johnsgard 1978, del Hoyo et al. 1992) (e.g. Chara spp. (del Hoyo et al. 1992), Hippurus spp., hornworts Ceratophyllum spp., pondweeds Potamogeton spp., milfoil Myriophyllum spp. (Johnsgard 1978) and especially stonewort Nitellopsis obtusa (Ruiters et al. 1994)), although it will occasionally also take aquatic invertebrates (del Hoyo et al. 1992) (e.g. molluscs) (Johnsgard 1978), amphibians and small fish (del Hoyo et al. 1992). 

The nest is constructed of roots, twigs and leaves near water (del Hoyo et al. 1992, Kear2005b) on the ground in dense vegetation or on floating mats of vegetation amidst reedbeds (Johnsgard 1978). Although the species usually breeds well-dispersed, neighbouring pairs may sometimes nest as close as 30 m apart (Snow and Perrins 1998, Kear2005b). 

A study in the Czech Republic found that fish ponds with a fish stock density of less than 400 kg ha¹, water transparency of more than 50 cm, mixed fish stocks (e.g. tench and pike or perch) rather than monospecific stocks (e.g. of carp or other herbivorous fish species), and systems that include ponds with fish fry are more likely to have high abundances of aquatic vegetation and are therefore more successful in supporting breeding pairs of this species (Musil 2006).

The two main threats to this species are habitat degradation (Defos du Rau 2002) (e.g. through land-use changes) (Kear2005b) and hunting (Kear2005b) (e.g. the species is hunted in France, Portugal and Spain without any official hunting bag monitoring (Defos du Rau 2002)). The species also suffers poisoning from lead shot ingestion (Spain) (Mateo et al. 1998)and is occasionally drowned in freshwater fishing nets with mesh sizes greater than 5 cm (China) (Quan et al. 2002). Deterioration in the water quality of wetlands can reduce the abundance of stonewort Nitellopsis obtusa (which is an important part of the species's diet) (Ruiters et al. 1994), and it is susceptible to avian influenza so may be threatened by future outbreaks of the virus (Melville and Shortridge 2006). The species is hunted recreationally and for commercial purposes in Iran (Balmaki and Barati 2006).

Above: adult drake Red-crested pochard, winter plumage

Above: adult drake Red-crested pochard, winter plumage

Above: adult drake Red-crested pochard, winter plumage

Above: adult female Red-crested pochard

Above: adult drake Red-crested pochard, winter plumage

Above: adult drake Red-crested pochard, summer plumage (moulting)

Above: adult female Red-crested pochard

Above: adult female Red-crested pochard

Above: a flock of Red-crested pochards, winter 2011, Markermeer, the Netherlands