Marshall, 1945 Palau Dreula oceanica have repeatedly seen them flutter and hang upside-down on little twigs while they gobbled fruit - like huge chickadees. Birds which call are often concealed in foliage flush when you walk under them, and often you don't see them at all. These are the old birds which are wary & if you do get a glimpse you see they have the knob on bill. The young ones are tame - no knob - hence most often call are in. Restricted to the one habitat - don't go into mangrove areas like Ptilinopus. Very abundant - altho Japs claim to like them for food. Call is horrible enough, but not as hair-raising as Arons stotidus. Reminds me of Sea Lions barking. Harsh & rasping & deep-throated : " Arrrooo, arrrooo, arrroo, arrooo, aroo " 3 - 7 notes each a trifle lower in pitch & intensity than preceding, and each shorter than preceding. When very close, a superimposed tone is heard with rising inflection, high pitched rasp similar to Hyla or locust : kreek kreek kreek Note: large fruits swallowed never seen on the ground whole - see stomachs.