Marbled Frogmouth in the Sunshine Coast Hinterland

The plumiferus race of the Marbled Frogmouth, found only in south-east Queensland and north-east New South Wales, was truly enigmatic not so long ago. It had not been seen or heard for several decades until I found it in 1976 while camping with Glen Ingram along the upper Booloumba Creek in the Conondale Range. See this link for the paper published in Emu. The surprise is that it took so long for the bird to make its presence known. Subsequent surveys showed it was widespread in suitable habitat throughout its known range.

The Marbled Frogmouth is restricted to rainforest at all attitudes, favouring wet gullies with closed canopy, especially those with an abundance of Piccabean Palm, as in this image. Tree-ferns, Quandong, Brush Box and Rose Gum are among the trees that are common in its habitat.

The bird in the images above was a female in the western slopes of the Blackall Range, in the Sunshine Coast hinterland. I have found 11 pairs holding well-established territories over much of what is now the newly declared 10,400-hectare Mapleton National Park - see this link for the park announcement. Two pairs reside in adjoining territories and at the right time of year - late spring - three or four frogmouths may be heard calling simultaneously.
The Marbled Frogmouth is widespread in the nearby Conondale Range; birds continue to reside at sites in the Conondales where they were present in the mid-1970s. The frogmouths are particularly vocal in spring and summer but can be heard at any time of the year.

The Marbled Frogmouth and the much more common Tawny Frogmouth, pictured here, often occur in close proximity to each other, though the Tawny is rarely inside rainforest - and the Marbled is rarely outside rainforest. They are of similar size and the male Marbled shares the Tawny's general greyish colouration, but the female Marbled is much browner.
Contrary to what the field guides show, both have extended plumes above the bill and while Marbled typically has deep orange eyes, the eye colour of Tawny is variable and may be quite bright orange. Marbled appears blotchy on the underparts and upperparts, while Tawny is finely streaked. 

Both have a pale supercilium although it is more apparent and sharply defined in Marbled, as this image shows well. Marbled also looks longer-tailed. The calls are substantially different.