Birds nests harbor insects and mites which live as scavengers on the nest material, or droppings, or as external parasites on the birds.To reduce the number of bothersome birds over time, you can limit the next generation by removing nests or destroying eggs. For English sparrows or feral pigeons, remove eggs at two-week intervals in the spring and summer. To gradually decrease pigeon or duck flocks, feed the birds so they don’t reproduce.
http://bit.ly/2eaQfh8