It's no permanent loss. Convergent evolution will bring back functional equivalents of those species in time as new waves of urban decay and backlashes against safe, wholesome neighborhoods wash over the cities. Convergent evolution is the same mechanism that caused some mammals look like sharks, some to look like birds, and some to look like Elvis.

There have been some sitings of colonies of them in the subways of Boston as well. Still, mating pairs are extremely rare, or really, unheard of.