Saturday 2 July 2016

29-6-2016 RACO DE OLLA, VALENCIA - BLACK WINGED STILT (Himantopus himantopus)


Black-winged stilts (Himantopus himantopus) are very long-legged wading birds. They are found in both warm and hot climates, feed on small aquatic creatures, and nest on the ground surface in small colonies.

Adult Black-winged stilts have long, pink legs, and a long, rather thin black bill. They are generally black above and white below, with a white head and neck. Males have a black back, often with a greenish gloss or sheen. Females' backs have a brownish hue, contrasting with the black remiges. In populations where the top of the head is normally white (at least in winter), females tend to have less black on the head and neck the entire year round, while males often have much more black, particularly in summer. 


This difference is not clear-cut, however, and males usually grow all-white head feathers in winter. Immature birds are grey, instead of black, and have a markedly sandy hue on their wings, with light feather fringes appearing as a whitish line in flight.


Black-winged stilts are found across Europe, Asia, Africa, Australia, and North, Central and South Americas. Some populations are migratory and move to the ocean coasts in winter; those in warmer regions are generally resident or short-range vagrants. Black-winged stilts breed in freshwater and brackish marshes, shallow lakes, ponds, and flooded fields. They can also be found in mountainous areas near lakes, river deltas, estuaries, coastal lagoons and marshes, salt meadows, and mudflats.

Black-winged stilts are very gregarious birds. They often gather in groups of around 20 individuals and may migrate or roost in large flocks of several thousand birds. Black-winged tilts are mainly diurnal; however, they are also adapted to nocturnal vision and may also forage even on moonless nights. Black-winged stilts feed in shallow water, wading slowly picking up their food from the water surface or sand. 


Black-winged stilts are serially monogamous; they form pairs and maintain their bonds only during one breeding season. These birds may nest singly or in loose colonies and each pair defends vigorously their nest site and territory around it. The nest is a bare spot on the ground located near water. The female lays up to 4 eggs which are then incubated for about 3-4 weeks by both parents. Chicks hatch well-developed and can leave the nest within 24 hours. They fledge around 1 month after hatching and become independent 2-4 weeks later. Young Black-winged tilts become reproductively mature and start to breed when they are 1 or 2 years old.

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