Muir's corella formerly inhabited woodlands and open country east of the main area of forest in south-western Western Australia, occurring north to the Swan and Avon Rivers, south to Albany and Augusta, and eastwards to the Stirling and Porongurup Ranges.

[2] The corellas forage on the ground in large flocks and feed on a wide variety of seeds of both native and introduced plants, as well as corms and tubers which they dig up using the elongated upper mandibles of their bills.

Cereal grains, including oats, barley and wheat, are eaten extensively in summer and autumn, while the corms of onion grass are important in winter and spring.

[2] Muir's corella is considered to be threatened because it consists of one relatively small and isolated population covering a fragmented range of about 3000 km2, with the actual area of occupancy being about 500 km2.

[2] While current nest hollow and food availability are sufficient to sustain the population, changes in land use may threaten the corella where remnant vegetation and paddock trees are cleared to establish plantations of blue gum and other species.

It is potentially threatened by competition from, and interbreeding with, a species introduced from south-eastern Australia, the closely related long-billed corella, which has nearby populations established from avicultural escapes and releases.