Some of the swallows do not fly away to warm lands in the fall, but remain with us. Some of them fly away to the nearest mountains and they can often be found there sheltered for the winter in rocky crevices. " According to another version, the swallows "hide in swamps, dive under water and winter there".
In old books describing nature, you can read about the war between swallows and sparrows. Swallows, returning from distant southern countries in the spring, find their nests occupied by other residents. Impudent, practical and lazy sparrows move into empty swallow nests in winter. Swallows declare war on the sparrows and fight until they drive the invaders out of their nests.
If they cannot cope on their own, they call the neighbors for help and then “a lot of swallows gather, which bring dirt in their beaks and cover up the entrance to the nest so that the insolent sparrow sitting there suffocates” (Mishkolchi).
One can hardly believe in such sophisticated cruelty on the part of cute swallows, but as for the seizure of someone else's home by "impudent, practical and lazy" sparrows, we can see for ourselves if we wish.
For millennia, the imagination of people was struck by the biblical parable of the devout Tobias, blinded by swallow droppings. “The pious Tobias got into the eyes of a swallow droppings, which made him blind. The sight returned to him only due to the fact that he smeared his eyes with fish bile."
Swallow droppings are indeed very pungent and we could say together with Miskolchi: “No wonder old Tobias went blind when he got swallow manure in his eyes. However, it is possible that poor Tobias was suffering from trachoma, like many at the time.