Introduction:The past-two-decades have faced many-viral-epidemics. The present threat-COVID-19 causes great-loss of human-lives, change human-civilization, public health, agriculture, travel, socioeconomic, education, civil-engineering, environmental-sciences and clinical-research also. There are no proper-effective-treatmentmethods. The low-income-households, senior-citizens, and street-children are not able to manage. So the whole world as well as the Government of India tries to reorient for the COVID-19 epidemic-crisis, by developing policy-initiative. So it is emphasis on the conservation of biodiversity, agriculture, socio-economic, civil-engineering, and environmental-sciences, for preventive-measures against "21st century-various-human-diseases like COVID-19-Pandemic".Methods: In the two ecofriendly localities; rural and urban areas, where constructs or set up different types of artifi cial-nests in the building as well as in the trees, rainwater-harvesting with fi shery, and nutritional-garden, forming the common-complex-ecosystem with landscaping by trees, garden, midday-meals, store-grains reservoir's, playground, pond, and river with agriculture.Result: Various kinds of birds, rats, mice, moles, bats, squirrels, mongooses, insets, toads, snakes, and other animals, are the regular visitors. But the owls apparently act as a keystone-species within these food-chain-relationships. Rats that happen to spoil food items of mid-day-meals, store-rooms, and documents are checked by barn-owl. Bats make building dirty by their excreta are also controlled by this owl. Different pests and mongoose, which are found to signifi cantly reduce food production in agriculture, pisciculture, tsar-industries, hatcheries, and poultry-farm, are appreciably kept on top of things. And, improves midday-meal, arouses the interest of locality on ecology-food-chain-relationships-issues, and contributes to sustainable-pisciculture-pond, agriculture, and kitchen-garden-management, micro-and macro-climate issues, and also community-health also. It's worth mentioning that the hooter plays the role of the simplest carnivore, predating on mongoose juveniles and bats, the