The western fieldwren (Calamanthus montanellus ) is a species of bird in the family Acanthizidae, endemic to southwestern Australia. It is often considered a subspecies (Calamanthus campestris montanellus ) of the rufous fieldwren (C. campestris ), most notably by Christidis and Boles in their 2008 work, but as a separate species by many other authorities including the IOC.