Karnala Bird Sanctuary covers 4.5 square kilometres of tropical moist deciduous forest at the base of the fort hill. It is small by the standards of Maharashtra's wildlife areas, but the forest is dense and diverse, and the combination of lowland scrub, riparian woodland, and higher-elevation jungle packs in a wide variety of species in a confined area.
The best birding is in the early morning — arrive at the gate by 6am if you can. Common sightings include hornbills, Malabar whistling thrush, barbets, flowerpeckers, drongos, and a range of raptors overhead. Migrants arrive from October through March, including warblers and flycatchers. A Maharashtra forest department permit is required; buy it at the entrance gate. Guides are available and recommended for serious birders.