Biology and ecology of white stork

White stork settles at the opened landscapes with appropriate feeding conditions – meadows, swamps and grasslands. It prefers wet territories with short grass and with groups of old trees with branchy crown, especially if this grasslands are periodically flooded and grass is regularly mown clean. After flooding, here are a lot of different small animals that white stork feeds. Haying also promotes rich hunting. After haying insects, rodents and amphibians fall an easy prey. That is why natural meadows on the unregulated rivers are the most favourable for white stork in our conditions. Density of birds in such places could reach tens of pairs on 100 square kilometres. Ploughing-up of flood-plain makes forage capacity of lands worse. White stork avoids high grasslands. You will never find it on the wheat field, which came into ear, or in the maize.

Birds make nests on the lonely big trees, different buildings, electricity poles, water towers, etc. Among trees they prefer those that growth near houses or in branchy top of trees. According to counts of 1987 in Ukraine, more than half of nests were built on the top of poplars, ash-trees, pussy-willows and oaks.

White storks are long-standing human companions. It willingly settles in settlements, sometimes even in cities. But it is also possible to found the nest on the low stump in the marsh.

If there is lack of place for nests in usual habitats, birds open up new. In this way, birds quickly rendered habitable electricity and telephone poles. Number of such nests increased little by little and now their rate is more than in “traditional” places.
Location of nests changed considerably during last decades from 68% on the buildings in 1931 (data for the territory of Ukrainian Soviet Republic) to 20% in 1987–1988, 13% in 1994–1995 and 9% in 2004–2005. Number of nests on the poles and water towers steadily increased. Number of nests on the trees first increased to one and a half time and then started to reduce. It varied in the range of 30–45%. This trend is common for many countries. White storks started to live even at the railway stations, making nests on the poles of contact system. Noise of trains does not bother them.

Usually white storks settle in pairs and are not friendly to nearest neighbours. Sometimes human attempts to attract these birds with hand-made nests are unsuccessful because neighbouring pair banishes new inhabitants away. But from the other side sometimes white storks live in real colony even of several nests on the same tree.
In spring, white storks usually come back to breeding places of the last year, but not necessarily to the same nest. The birds build new nests rare; mainly they repair and overbuild old ones.

White storks that nest for the first time usually come back to the native place, but only sometimes they could settle in the parental nest, mostly in some distance from it. Observations in different countries have shown that about two thirds of juveniles nested for the first time in 50 km distance from the parental nest. Part of birds nest in much further distance up to hundreds of kilometres.

White storks fly back in the second half of March – beginning of April, rarely it is possible to see them in the beginning of March. Some of birds could stay till May. Usually males arrive first, more rare females, sometimes both. Females arrive in several days after male. Old birds arrive earlier than juveniles.

A nest is made from sticks. Strong and long sticks create a basis, smaller ones overlay them. Inside of nest birds put hay, grass, moss, sometimes paper, rags, manure, pieces of cellulose, etc. In the beginning, the nest is about a meter in diameter and some tens centimetres in high. Sometimes it could be even flat. Probably its size depends on when birds started nesting. As earlier they start as much time they will have to build the nest. During years the nest is overbuilt and becomes bigger. Sometimes this lasts to tens of years and reaches 2 meters in diameter, 3-4 meters high and 1-2 tonnes weight.

It is rather a laborious work to build or repair the nest. Sticks usually fall down, especially from the basis of the nest so it is needed to put them back over and over again.



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