|The Palm Cockatoos' distribution,
indicated in red, ranges from parts of New Guinea, the Aru Islands and
the Cape of York Peninsula in Northern Australia. There are considered
to be 3 subspecies, which are mainly different in body size and crest.
The Aterrimus which is the nominate subspecies is the smallest and ranges in body weight from 540 grams to 825 grams in the males and 500 grams to 675 grams in the females. They are between 55 to 60 cm. in length. The Stenlophus is larger than the aterrimus and slightly smaller than the Goliath, but I have not been able to find any definitive information on this subspecies except that it is written that it is similar in size and has a smaller crest than the Goliath. The Goliath is the largest of the three, ranging in body weight from 1000 grams to almost 1300 grams in the males and 850 grams to around 1000 grams in the females. I have heard reports of 1300 gram males but none have been confirmed. Their body length is between 60 to 70 cm.
The males and females not only differ in body weight and size but there is a dramatic difference in the size and shape of the head. The maxilla or upper mandible is much more delicate in the females and the red skin patches are much larger in proportion to the size of the head in the males. In general the coloring of these birds is the same between the males and the females. Their plumage is black to dark gray with bright red cheek patches which are not feathered but are bare skin that changes in intensity with excitement and increased blood flow to the small capillaries laying under the surface of the skin.