There is an interesting fruit bat roost in the grounds of the old governors residence (a nice colonial era building). This is behind the market on the first road off the river. If the gate to the old governors building is open, you may be in luck, the house itself is sometimes left unlocked. All of the original furnishings are missing, but some of the bathroom fixtures remain and the house itself gives off a haunted vibe.
The grasslands and rice-fields surrounding Kompong Thom of an extreme importance for wildlife conservation. These areas hold the largest global population of the endangered Bustard the Bengal Florican as well as occasional large waterbirds from the Tonle Sap floodplain (Adjutants, Pelican, Painted Stork). Other species include large numbers of wintering palearctic passerines (including Dusky Warbler, Yellow-breasted Bunting, Siberian Rubythroat) and the globally vulnerable Manchurian Reed Warbler. In March large numbers of Oriental Plover pass through the area making this possibly the best area in the world to see this species.
The areas also offer a glimpse of everyday life in the Cambodian countryside with many fishermen, ox-carts and small scale farmers. The best way to visit the grasslands is by en-listing the help of a moto-dop driver from in-front of the Arunras guesthouse. A number of these know the area (around Rolous village about 5km towards Phnom Penh) and speak English.