In spring, domestic swallows fly back to the north from the south. After nesting with mud, the female swallows lay 4-5 eggs, and then hatch for half a month, and the young swallows are born. A pair of swallows can hatch twice a year, when the swallows work harder. A pair of swallows feed a nest of swallows at least 15 times an hour and 180 times a day, catching an average of 450-500 pests every day, and adding their own food, the total number is more than 600. A simple calculation can be made: a pair of domestic swallows and their two young swallows can eat 500,000 to 654.38 million insects in 180 days from April to September. What an amazing number! Mosquito rope is the main pest eaten by swallows, as well as agricultural pests such as locusts, moths and mole crickets. It has been calculated that a swallow can eat 540 locusts a day, and the pests eaten by a swallow in summer are connected end to end, which is a whole kilometer long! Someone caught Swift during the incubation period, and there were 370 bugs in its wide and long mouth. Therefore, in an incubation period, a nest of swift will eat 250 thousand bugs.
Swallows kill a lot of insects and make great contributions to agricultural production. If there are 5,000 corn plants in an acre of corn field, and there is a bug on each corn plant on average, then a pair of house swallows and their chicks can get rid of the bugs in 200-400 acres of corn field. In other words, the pest control ability of a nest of domestic swallows is equivalent to the effect of spraying pesticides by 20 to 40 farmers. Moreover, drug pest control will cause environmental pollution, which is not conducive to human and animal health, especially for sericulture and beekeeping in rural areas. At present, all countries in the world advocate making full use of biological control of pests, and using swallows is a very effective method of biological control of pests.