Storm’s Stork

INTRODUCTION:
The Storm’s Stork is included in the subfamily Ciconiini which gathers seven species of genus Ciconia, the “typical” storks. This monotypic species was formerly a subspecies of the Woolly-necked Stork, and both are fairly similar.
It occurs rarely in small groups, and is usually seen alone or in pairs in a variety of wet forested areas.
The Storm’s Stork is an Endangered species, threatened by habitat loss throughout its range.

PROTECTION / THREATS / STATUS:
The Storm’s Stork is one of the rarest storks and the small population is estimated at 260-330 mature individuals throughout the range. This fragmented population is still declining.
The species is threatened by habitat loss through destruction of forest (logging), dam construction and conversion to oil-palm plantations. This shy and secretive bird is disturbed by humans on rivers used as travel routes, involving rapid declines.
The Storm’s Stork is protected in Thailand, Malaysia and Indonesia, and it occurs in several protected areas throughout the range. But currently, the species is listed as Endangered.

DESCRIPTION OF THE BIRD:
Biometrics:
Length: 75-91 cm

The Storm’s Stork adult has black and white plumage, with glossy black wings, back, crown and breast, whereas throat, hindneck, belly and vent are white.
On the head, the crown is black. The bare yellow facial skin extends broadly around the eye from lores to ear-coverts, while the face is dull orange.
The long bill is bright red with slightly concave culmen and basal knob in male. The eyes are red. Legs and feet are reddish.
The female is similar but she has straight bill and the basal knob is lacking.
The non-breeding adults have duller bare parts.
The immature has browner plumage than adults. The bare parts are duller, with dark-tipped bill. Face and throat show black markings.

RANGE:
The Storm’s Stork is found on the Malay Peninsula, with very small populations in S Thailand and Peninsular Malaysia, Sumatra where it is resident, and Borneo where the species is widespread but scarce.

HABITAT:
The Storm’s Stork frequents freshwater swamp forest, rivers, streams and pools in evergreen forests, and densely forested areas. It usually occurs in lowlands, up to 240 metres above the sea-level.

CALLS AND SONGS: SOUNDS BY XENO-CANTO
The Storm’s Stork is usually silent outside the breeding season during which they may produce various vocalizations and noises at their breeding sites. The displays at nest are accompanied by bill-clattering.

BEHAVIOUR IN THE WILD:
The Storm’s Stork feeds primarily on fish, but it also takes frogs, reptiles and large insects. Thanks to the long legs, it wades through water or tall grass, and takes the preys from water or ground with the long, pointed bill. It forages in swampy forests or muddy riverbanks by walking, probing and pecking. It may forage in small groups of 7-12 individuals, but it is more often solitary or in pairs when feeding.

The Storm’s Stork performs the typical displays of Ciconiidae during the breeding season, and both mates can be seen together during aerial displays. At nest-site, the bill-clattering display is common and accompanies various ceremonies between mates.
Male and female of a pair stay together for several breeding seasons, and the same nest is often reused on several following years. The birds regularly add more material each year, and the structure is sometimes impressive.

The Storm’s Stork is suspected to wander great distances, and some birds have been observed several kilometres from their suitable areas in Sumatra. This species probably moves in response to habitat loss.

Like numerous Ciconiidae, the Storm’s Stork uses its long, broad wings for soaring, and it flies with outstretched neck. Soaring is often interspersed with flapping.

REPRODUCTION OF THIS SPECIES:
The breeding season probably starts in August-September until November in Borneo. But the breeding behaviour of this species is poorly known.
This species is solitary nester. The large stick nest is built in tree fork and is reused year after year. This structure is made with sticks and lined with dry leaves and some down. The nest is placed between 19 and 30 metres above the ground, usually in tall tree.

The female lays 2-3 white eggs, and both adults incubate during about 25-28 days. The chicks have white down, bald dark crown, brown eyes, yellowish legs and feet, and dark bill with yellow-orange tip. The female tends the chicks but both parents feed them by regurgitation onto the nest’s floor, where the smallest chick takes it easily.
They fledge 52-57 days after hatching and are fully feathered.