The White Storks barely ever made any sound as a voice. In the birds world this is quite an unusual circumstances. The stork's vocal organ of a bird it's so immature that it can't produce sounds.
The white stork is almost silent except for the noisy mutual bill clattering when adults meet at the nest.
Though storks are considered to be largely silent birds, most species perform some variety of a bill-clattering display. This display reaches its most advanced form in the White Stork. They begin by throwing their heads straight back to create an amplifying resonance box in the throat pouch of the lower neck. As they clatter their upper and lower mandibles together rapidly they produce a sound very loud just like a machine gun rattle that rises and falls in pace.
In most situations throughout their lives storks do not need vocal communication at all. The storks live in open land; they are large birds of distinct colors, so they are well visible from the distance and they can find enough visual signals to maintain contact with their family members.
Only sometimes, when standing in the nest, a stork happens to "say something". Widely known is the ceremony of greeting. Its aim is to recognize partners coming back home, suppress aggression and abstain from the automatic reaction of protecting a nest from intruders.
When one stork is standing in the nest and another one flies towards it, they start the ritual of gestures with their heads, necks and wings, accompanied by long, loud clattering of beaks. Simultaneously storks produce silent sounds by letting the air go through the trachea. In most cases it is a short humming whistle or a hiss reminding a loud whisper, rarely - a hoarse purr.