
I think the Common Flameback, Dinopium javanense, has to be one of the most colorful birds that can be seen in our urban spaces and heartlands. I have seen them at the car park at the Alexander Hawker Center visiting the shade trees there. A pair regularly comes to forage on the rain tree outside my balcony. Their calls can be heard often all over our urban landscape.
A female Common Flameback chipping out grubs from a rotten branch of a Yellow Flame tree
But it was not like this before. Even though it was a common resident then, it was noted by Bucknill and Chasen (1927) that they avoided towns and stayed in the rural and cultivated areas, mangroves and forest patches. They are also found in our offshore islands of St. Johns, Sentosa and Ubin.

Lim and Gardner 1997 recorded them in coconut plantations, coastal scrubs, orchards, parks and gardens on the mainland. The other woodpecker that followed their spread to the urban landscape is the Sunda Pygmy Woodpecker, Dendrocopus moluccensis.

I think it had to do with their food sources and places to build their nests. Rain trees and other soft wooded roadside and shade trees provide them with abundant grubs and caterpillars to feed on. The rotting branches and peeling barks on the tree trunks are places where these grubs strife. These old branches also made for good and easy nesting holes. Over time when they have adapted to the noise and our presence, they are safe with no predators around.
Reference: Lim Kim Seng. The Avifauna of Singapore. 2009. Nature Society (Singapore)