On the other hand, pigeons do face a number of predators, including peregrine falcons and cats, whilst their nests are often targeted by opossums, raccoons, crows, and owls. But regardless of them not being aggressive, humans should still keep their distance because, like rats, pigeons still carry a number of diseases. 

Their feces in particular can be an issue, as they tend to excrete a lot, and it can attract other pests like insects or even other pigeons, as well as spread diseases and encourage mold to grow if left alone for long.

Estimates suggest there are well over 400 million pigeons in existence today, which is undoubtedly a testament to their survival skills and ability to evade and outwit humans at every turn. Like rats, pigeons have a varied diet that makes it very difficult to prevent them from eventually causing a problem. Whilst they naturally tend to eat things like grain or seeds, they have adapted to urban areas, especially in cities where food is, purposefully or otherwise, in abundance.

Despite their reputation, however, pigeons are remarkably smart creatures. According to one study, pigeons may be the only creature that is not a mammal that can recognize themselves in mirrors, which also makes them one of just six species in the world that can. They are also renowned for their navigation abilities; it is theorized that homing or messenger pigeons use magnetic field lines, as well as their other senses, to return home.