> "But Wilson says the population has steadily grown, and he estimates between 30 and 50 wallabies live on Lambay today."

There's also a small population of Brush Tailed Rock Wallabies living in Kalihi valley on the island of O`ahui, Hawaii. The are descended from a pair that escaped from a private zoo in 1916 [1].

Estimates on the population vary, but the state estimated it reached as high as 75 animals in the 90's [2].

Occasionally someone will snap a photo of one, such as this one in 2013 [3].

[1] http://en.wikipedia.org/wiki/Brush-tailed_rock-wallaby#Intro... [2] http://archives.starbulletin.com/2007/08/18/news/whatever.ht... [3] http://www.hawaiinewsnow.com/story/22589173/woman-snaps-pict...