Description of the species

The white stork (Ciconia ciconia) belongs to the order of wading birds (Ciconiiformes) and the family of storks (Ciconiidae). This family consists of 5 genera which comprise 19 species of birds living on both hemispheres. The family is divided into three subfamilies: Mycteria, Ciconia, and Leptoptilos.

A standing stork is about 80 cm tall. An adult bird weighs from 2.7 to 4.5 kg, and the wingspan reaches 2 m.
The stork has characteristic red legs, white plumage with black remiges, a long neck and red beak.

Food

The storks are not picky eaters. They take advantage of what is most available at the moment. Their diet varies depending on the area, season, and the weather conditions. The white storks hunt for invertebrates such as snails, earthworms, beetles, grasshoppers, or larvae. Apart from that, they feed on fish, amphibians, reptiles, and even chicks of birds nesting on the ground. Among the important components of their diet are rodents (mainly voles). While hunting, the storks walk around their feeding ground and seek their prey (the so-called feeding ground search). They can also wait motionless, for example by the rodents’ holes, like the herons do. They willingly seek food during field works, hay mowing, or harvest. In spite of the tales we have heard in our childhood about storks hunting frogs, those amphibians are only complementary components of the storks’ diet.

Behavior

The stork is a species which inhabits the farming landscape and its existence is connected mainly with wetlands where the largest concentrations of nests are observed. The storks build their nests near human houses on trees, utility buildings, and recently, on operating power line poles (over 60% of stork pairs in Poland nest on power poles).

The birds return from their overwintering areas in late March or in April. Just after arrival, they fix their old nests or begin to build new ones. They reach sexual maturity at 3-5 years of age and they breed for the first time. During the breeding, the male clatters loudly with his beak and throws his head back so far that it rests on his back. The first eggs are usually laid in mid-April.
There are usually 3 to 6 eggs in the nest which are incubated in turns by both parents. The incubation period is 33-34 days, and after 54-63 days, young storks leave their nests. Depending on the breeding date, the offspring’s fledging can stretch from early July until early September. The storks spend about 5 months in Poland after which, from mid-August, they gather in flocks (the so-called sejmiki) and fly away to their overwintering areas in Africa. The birds which did not breed in a given year and young ones leave as first.

Population
The breeding range of the white stork covers most of Europe (apart from the British Isles and the Scandinavian Peninsula), Asia Minor, and North Africa. The population size of the white stork in Poland is estimated at about 52 thousand pairs (data of 2004). Approximately 1/5 of the world’s white stork population nests in Poland. This makes us responsible for the birds’ fate, all the more that its population has been decreasing in the past few years.

ADULT BIRD

  • Wingspan: 2 m
  • Height: 80 cm
  • Weight: approx. 3-4 kg
  • Beak length: 15-20 cm

NEST

  • Diameter: 1-2 m
  • Height: 0.5-1.5 m
  • Weight: approx. 500 kg

EGG

  • Number: 2-5 (in rare cases 1 or 6)
  • Dimensions: 74 x 52 mm
  • Incubation period: 33-34 days

CHICK

  • Period of staying in the nest: 54-63 days