Ferruginous duck

Aythya nyroca Güldenstädt, 1770

General distribution (range). Wide but discontinuous area, Western and Southern parts of the Palaearctic region. Northern limit of the range is located on the 23 °C isotherm of July; the southern limit largely corresponds to the 32°C of the same month. It is located from South-Western Europe to Central Asia.

Distribution in Romania. Danube Delta, Braila Small Island and wetlands within the country (lakes, large ponds, reservoirs), where rich reed surfaces are present, alternating with open water surfaces, Generally, more present in South-East and Western part of the country.

Habitat. Ponds and eutrophic lakes, with abundant aquatic/floating vegetation (including reed) and open water surfaces. It prefers natural aquatic basins, but it nests also on ponds or partially clogged reservoirs, on which vegetation developed; in the last years, they populate more and more frequent the abandoned fisheries from the delta, which are now invaded by floating plants.

Biology. Summer guest (months III-X). Rarely wintering in Romania, being sensitive to lower temperature. It nests relatively late (months V-VII). Where old willow-trees are present, the nests are located in hollows. A complete clutch contains 8 to 12 eggs. Incubation lasts 26 to 28 days. The juveniles follow their parents shortly after they hatch. The food consumed by the ferruginous duck is mainly vegetal.

Limitative factors. The factors that contributed to the reduction of the ferruginous duck population in Romania are: lakes and natural ponds reclamation, habitats degradation (through excessive eutrophication, aquatic vegetation degradation, clogging or increase of water turbidity. These phenomena are generally caused by human activities developed in surrounding terrestrial environments or by transformation of natural water bodies in fisheries (which includes also reed surfaces destruction). Because it nests so late, when the hunting season traditionally opens on August 15th, several young birds do not have complete flying skills; occasionally, ferruginous ducks get caught and die in fishing nests; predation is caused mainly by invasive small carnivores (i.e. American mink). It is possible that similar to other countries (Slovenia, Austria, Hungary), the introduction and breeding of plant-eating fish, massively consuming aquatic macrophyte, had a negative impact also on the ferruginous duck (due to the reduction of its basic food resources).

Protection. The ferruginous duck is protected by the Law 13/1993 (Bern Convention, Annex III), Law 13/1998 (Bonn Convention, Annex II), Law 89/2000 (AEWA- Annex 2), Birds Directive 79/409/EEC, OUG 57/2007 regarding the protected areas regime, conservation of natural habitats, flora and wildlife (Annex 3), Law 407/2006 and 197/2007 – Hunting Law (Annex 2 – hunting is banned). The study of the actual trend of ferruginous duck, dealing with knowledge on the habitats they occupy and those that they eventually migrate to, and also the preferential food with respect to the food offer will represent ways to understand the vital requirements of this species. The strict enforcement of the existing regulation regarding hunting is required and also, the inclusion of the main wetlands populated with the ferruginous duck in special protection areas for bird protection.

IUCN Status. Near Threatened

Birds Directive. Priority species