The Forty-spotted Pardalote (Pardalotus quadragintus), is by far the rarest pardalote. It is found reliably only in a few isolated colonies on south-eastern Tasmania, most notably on Maria Island and southern Bruny Island. It is occasionally reported from the suburbs of Hobart. Sedentary or locally nomadic over its restricted range, it is declining in numbers. It is most successful on Maria Island, which is managed as a refuge, with introduced predators having been eliminated.
About 3.5 to 4 inches long, it is similar to the much more common Spotted Pardalote, (Pardalotus punctatus), but has a dull greenish-brown back and head, compared to the more colorful plumage of the former, with which it shares range, and there is no brow line. Rump is olive, under-tail dull yellow. Chest white with light yellow tints. Wings are black with white tips, appearing as many (40 to 60) discrete dots when the wings are folded. Juveniles are slightly less colorful then adults.
Relatively dry Eucalypt forests with high concentration of the Manna Gum (Eucalyptus viminalis), is where it forages almost exclusively. It forages mainly for small insects. It nests in tree hollows.