So overt it's covert: Wildlife coloration in the city

With novel human-wildlife interaction, predation regimes, and environmental conditions, in addition to often fragmented and smaller populations, urban areas present wildlife with altered natural selection parameters and genetic drift potential compared with nonurban regions. Plumage and pelage coloration in birds and mammals has evolved as a balance between avoiding detection by predator or prey, sexual selection, and thermoregulation. However, with altered mutation rates, reduced predation risk, increased temperatures, strong genetic drift, and increased interaction with people, the evolutionary contexts in which these colorations arose are radically different from what is present in urban areas. Regionally alternative color morphs or leucistic or melanistic individuals that aren't typical of most avian or mammalian populations may become more frequent as a result of adaptive or neutral evolution. Therefore, I conceptualize that, in urban areas, conspicuous color morphologies may persist, leading to an increase in the frequency of regionally atypical pelage coloration. In the present article, I discuss the potential for conspicuous color morphs to arise and persist in urban mammalian and avian populations, as well as the mechanisms for such persistence, as a result of altered environmental conditions and natural selection pressures.