Dendrocigna maculata

Identificazione

The Spotted whistling duck is one of the smaller species in the genus Dendrocygna. This duck grows to 43–50 cm tall. Males can weigh anywhere from 590g to 650g while females weigh 610g to 860g. White spots on their flanks and breasts gave these ducks the spotted name. The sides of the neck, faces, and eyebrows are all grey. Black or dark brown coloring stretches from the crown nape to the hindneck. This dark coloring is also found in the eyepatch. Their coloring resembles a cape with a thick collar. This cape starts as a light brown then fades into a darker brown closer to the tail. Their underbelly is mostly brown, sometimes spotted, and significantly lighter than the wings and the “collar.” A white bar on the upper tail coverts can be seen during flight aiding in identification. They have dull pink legs with black webbed feet and sharp nails. The bill is dark, yet often seen with portions of red and a small white mark on the lower mandible. Spotted whistling ducks look as though they are raised from the ground, as though they are standing up tall. (look more into this). Their wings pressed strongly against the body. Inner vanes of the outer primaries are jagged and can be seen in flight (check on this). While flying, the head is positioned down causing the whole bird to look hunched. The tail stays pointed and looks long when in flight. Juveniles are seen with white streaks on flanks instead of spots and have significantly duller coloring. Spotted whistling ducks are visually similar to D. arborea, yet many scientists believe its closest relative is D. eytoni. After gaining their adult plumage at the age of 6 months,. the spotted whistling duck has a single annual molt. Like other ducks, swans, and geese, the spotted whistling duck molts synchronously. Synchronous molting is common within Anseriformes because waterfowl have the ability to avoid terrestrial predators. Unlike other birds, waterfowl float in ponds lakes while they molt, safe from predators. Other more evolved ducks have two molts, whistling ducks only molt once.

Tassonomia

Nome scientifico

Dendrocygna guttata

Autorità

Schlegel, 1866

Ordine

Anseriformi

Famiglia

Anatidae

Genere

Dendrocigna

Areale e habitat

Whistling ducks are found all over the world. The spotted whistling duck is distributed throughout the Philippines, Australia, and New Guinea. These ducks live in the southern part of the Philippines and several islands of Indonesia. In Indonesia spotted whistling ducks stretch from the Eastern Lesser Sundas islands to new guinea. Spotted whistling ducks are also found in Weipa and Iron ranges of Australia, but have also been seen at Wonga Beach. Scientists hypothesize the Indonesian population was introduced due to a storm blowing the birds off course. Spotted whistling ducks live around bodies of water, like many other ducks. These ducks specifically live around small ponds and marshes surrounded by trees. They prefer humid and low altitude habitats. Spotted whistling ducks build hollows within the trees surrounding their habitats.

Migrazione

Resident species

Comportamento

Spotted whistling ducks are found in groups with their own species and often with D. arcata. Compared to others in the genus, these ducks are less vocal. These birds perch on tree branches in groups slightly smaller than flocks. The flocks are often a mix of adults and juveniles. The adults shepard the juveniles keeping them close to the group. In 2000 Beruldsen observed a group consisting of 6 juveniles and two adults, male and female. The juveniles seemed unbothered by the human presence, but the adults made sure there was distance between Buruldsen and the juveniles. The birds kept their distance but seemed to be unaffected. The adult male positioned himself between the juveniles and the humans, protecting the other birds. This behavior was often accompanied by several high-pitched ticking calls.

Conservazione

Tendenza della popolazione

stable