INTRODUCTION:

We would be tempted to say they are very similar, but if the appearance is almost the same except the plumage, these beautiful birds have their own habits and behaviours.

Both species show three main colours such as black, white and red.  
In White Stork, the pure white head, neck, underparts, tail and mantel contrast strongly with the black primary and secondary flight feathers. The long bill and legs are red. The eyes are brown to grey.
The juvenile is duller than adults and the bare parts are pinkish-grey to grey.
White Stork is slightly larger than Black Stork.   

All these symbols made these birds very well protected, whereas numerous large birds were persecuted.
However, declines regularly occur, and we have to care these beautiful birds if we wish to see them in the sky for long time.

ARDEA CICONIA

VOICES:

Both species are usually silent, but they produce some noises during the courtship and greeting displays.
White Stork is often heard producing bill-clattering while it throws the head backwards, helping the sound to carry at some distance.

Black Stork is able to produce varied kinds of whistles but it does not perform bill-clattering, or it is very rare.

DESCRIPTION:

The Black Stork has black plumage showing green and purple gloss. Lower breast, belly, vent and thighs are white. The bare parts, bill, legs and broad eye-ring are red.
The juvenile is duller and brownish, with greenish-grey bare parts.

HABITAT:
They breed in the warm parts of Europe, in North-west Africa and South-west India. Since several years, numerous breeding pairs remain in their breeding range all year round, according to the food resources and weather conditions. The young birds migrate.    

The Black Stork frequents more undisturbed open woodlands than wide open areas. It feeds in wet areas such as streams, pools, marshes and sometimes grasslands. This species avoids large rivers and dense forests.
The Black Stork is also a migratory species, with partially resident population in Spain.
They winter in Tropical Africa.
The South-African populations perform post-breeding dispersions, and mainly altitudinal movements.
Other populations winter from W Pakistan, through N India to SE and E China.
This species breeds across Palearctic, and we can find some local populations in Africa, from Malawi and Namibia to South Africa.   

RANGE:

The White Stork mainly frequents open areas and wetlands. This species is more terrestrial in Africa where the most part of the population winters. At this period, it is found in steppes and savannahs, grasslands, cultivated areas with pools, marshes and slow streams, lakesides, all with scattered trees for nesting.
This bird is strongly migratory, spending the winter in Tropical and South Africa and in India (Subspecies Ciconia ciconia asiatica).

BEHAVIOUR IN WILD:

Both storks hunt by walking slowly, watching for preys. When the prey is detected by sight, they snatch it up with the long bill.
White Stork feeds in drier areas than Black Stork which often hunts in shallow water, but both need wet areas for feeding. Black Stork feeds mainly on fish whereas White Stork prefers small mammals.
Their usual preys include fish, amphibians, reptiles, small mammals, large insects, and whatever kind of available food.

REPRODUCTION:

At the beginning of the breeding season, the White Stork male arrives first and waits for the female. It arranges or builds a new nest, helped later by the female.
White Stork nests in loose colonies, in trees, buildings, pylons, human structures or cliffs. The nest is reused year after year and may become huge. It is made with sticks, and lined with several kinds of items such as dung, paper, moss, grasses, plastics and debris.

Then, it is time for courtship displays. Male throws its head backwards, on shoulders, fans its tail, with rump raised at back level, with continuous wing beats. Sometimes, female joins it in this display. These displays, although less obvious, continue during the laying period and are often observed at nest.

In March-April, female lays three or four eggs and the incubation lasts about 34 days. The young fledge two months later and are sexually mature at four years.
They are fed by both parents with regurgitated food into the nest. After leaving the nest, the young birds fly with adults and return to the nest for sleeping and feeding.
This species produces one brood per year.

The Black Stork breeds in spring. It is a solitary nester and usually nests in trees in forests, but according to the range, this species may also nest on cliff ledges, always near water.
The large nest is made with sticks and lined with leaves, moss and grasses cemented with earth. It is reused year after year.
Courtship displays occur in late March. The Black Stork performs less elaborated courtship rituals than White Stork, with fanned tail and undulating neck. Both mates also perform flight displays.

Later, the female lays three or four eggs. Incubation lasts about 32 to 38 days, sometimes more. Young fledge 63 to 70 days later, and are sexually mature at three years. They are fed by both parents with regurgitated food into the nest.
Black Stork produces one brood per year. 

FLIGHT:

Storks perform elegant flight, gliding in thermal currents with stiff wings. The flight is strong and regular. The birds fly with outstretched neck and legs.
Black Stork performs more rapid wing beats than White Stork.    

PROTECTION / THREATS / STATUS:  

White Stork suffered declines due to habitat loss, mainly in feeding and breeding areas, with drainage of wetlands and deforestation. Collisions with power lines, hunting and use of pesticides in Africa are important threats too. The storks eat the poison baits intended to the large carnivores.

Unfortunately, both species suffer strong hunting during the migrations.
The Black Stork is threatened by deforestation and persecution. Drainage of wetlands and use of pesticides in Africa are the most important threats for this species.

The White Stork is often “seen” bringing babies in German legends. Thanks to this symbol, people encouraged the birds to nest on the roof of their houses, bringing fertility and prosperity to the owners.
In China, this bird is symbol of immortality.

The Black Stork is the bearer of new life in European folk legend.

Sources :

HANDBOOK OF THE BIRDS OF THE WORLD vol 1 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal – Lynx Edicions – ISBN: 8487334105

BirdLife International (BirdLife International)

Pájaros de España (JL Beamonte)

Wikipedia (Wikipedia, The Free Encyclopedia)