White-headed Malvasia

Description

White-headed Malvasia (Oxyura leucocephala) is a small anathid with a wide beak at its base, a large head, a compact body and a relatively long tail.

It is a species that presents sexual dimorphism, that is, the male and the female in their adult form are distinguished by their appearance.

As for the adult male, his head is white, with the exception of the pileus and nape, which are black, and are combined with the neck of the same color. They have a thick bluish beak in the breeding season, and it is dark gray when they are not in the breeding season. The rest of the body is light brown, with numerous black striations. The long tail points upwards and provides the bird with an unmistakable silhouette.

As for the female, it appears completely brown, with the exception of a clear band on the cheek and another on the chin. The beak is smaller and dark gray.

And finally, the juveniles have a color similar to that of the females, but without brown tones in the plumage and their dorsal color is darker.

Habitat and food

It is found in both freshwater bodies and brackish, alkaline water or eutrophic lakes. Breeding sites are characterized by good vegetation cover on the banks where the nests are located. Wintering sites have a larger area and less vegetation.

The white-headed malvasia is a diving species that generally obtains its food during dives, based mainly on aquatic invertebrate larvae and seeds and fragments of algae and aquatic plants.

Threats

The population of White-headed Malvasia has undergone a very rapid decline in recent decades, to the point of reaching only 22 specimens in 1977, mainly due to human factors, both direct and indirect, that threaten the conservation of this species, especially those caused by invasive species.

With regard to invasive species, the cinnamon malvasia stands out (Oxyura jamaicensis) and exotic fish species such as American carp or perch. Malvasia cinnamon, an undemanding and aggressive species, native to North America and introduced to the United Kingdom in the 1950s, from where it would spread throughout Europe. It poses a serious danger to our native species, since not only can it displace it from its habitat, but it is also capable of hybridizing with it, producing fertile specimens that jeopardize the genetic purity of the species. As for exotic fish species such as carps (Cyprinus carpio) represent another major threat due to their competition for food, and even large specimens of these fish can eat malvasia chickens.

Other threat factors include:

• The collision with power lines
• The burning of emerging vegetation, where they then nest
• The ingestion of lead pellets, which are used as gastroliths to crush food, or the ingestion of plastics, confusing them with worms.
• The use of pesticides
• Excessive hunting pressure or illegal hunting
• Habitat loss caused by climate change.

Other threats not related to humans are predation, parasites and pathogens.

Conservation measures

The white-headed malvasia is a species that is included in the Red Book of Birds of Spain as “Endangered”. In addition, it appears as “Endangered” in the National Catalogue of Threatened Species and is protected by a National Conservation Strategy, and some autonomous communities also have recovery plans.

The following lines of action affecting the species have been proposed: monitoring, control of cinnamon malvasia, surveillance of critical areas, elimination of alien animal species such as cinnamon malvasia, carp and American perch, control of lagomorphs and rodents, captive breeding and subsequent reintroduction in critical places for the species, correction of overhead power lines, elimination of lead pellets, elimination of hazardous materials for the species, maintenance of water levels in artificial wetlands and regulation of hunting and fishing activities.

As lines of action affecting the habitat, they have proposed the administrative protection of critical areas, the restoration of water quality and quantity, the acquisition of land in critical areas, the fight against erosion and filling, disposal of debris and waste collection, and habitat management to prevent infectious processes.

As lines of research, they propose genetic studies, monitoring and control of environmental parameters, inventorying wetlands, studying natural factors, improving knowledge of biology, ecology, toxicology, pathologies, migratory movements of the species and competition with other species.

In the area of education, outreach and citizen participation, they propose the preparation of a traveling exhibition, production of educational material, execution of campaigns, publication of field manuals and construction of observatories for public and scientific use.

Conclusion and recent data

The white-headed malvasia is a good example of a species that is on the verge of extinction, due to the threats mentioned above, and whose conservation measures have paid off. There is currently evidence in Spain that this species reproduces in wetlands in Andalusia, Castilla-La Mancha, Murcia and Alicante. Although the population of White-headed Malvasia has recovered, its conservation and that of other native species has not ended here, since the conservation of the natural environment is a long-distance race, especially if we want to enjoy it ourselves and future generations.

Bibliography

• Muntaner, J. (2001). Malvasía Canela's first date Oxyura jamaicensis in the Balearic Islands and conservation problems of the White-headed Malvasia Oxyura leucocephala.
• Torres Esquivias, J.A. (2009). The White-headed Malvasia (Oxyura leucocephala) during the early years of the 21st century.
• Salvador, A. (2017). White-headed Malvasia—Oxyura leucocephala (Scopoli, 1769).
• Moreno-Arroyo, B., Torres Esquivias, J.A., Vega Pozuelo, R. (2009). Influence of rubber bands on the conservation of White-headed Malvasia (Oxyura leucocephala): management and control in the lagoons of southern Córdoba.
• Www.seo.org

Diego Garcia, Biodiversity