Extract from "Owls of the World"
The collared pygmy owl (Glaucidium brodiei) ranges from the Himalayas and Assam hills (600 to 3000 metres) to western China, the lower Yangtze Valley, Formosa, the Malay Peninsula, Sumatra and Borneo. It usually lives in evergreen or mixed deciduous-evergreen forest, among oak, rhododendron and fir, but it also occurs in forest edges and more isolated groups of trees in cultivated country. This is one of the more diurnal species of the genus, and is often seen perching and hunting in broad daylight, though it is also active at twilight and at night. In this and many other aspects of its ecology, it resembles the Eurasian pygmy owl. The call, usually consisting of four musical notes repeated at intervals and distinctively grouped has been described as 'hu hu-hu hii'.

However, the bird on the stamp does not look like any illustration of Glaucidium brodiei I can find and may have been incorrectly labeled. I may do an identification feature on this stamp.