Most capture records come from areas of lowland rainforest to hill forest habitat but there is one record from lower montane rainforest. All species of Kerivoula show a strong preference for intact closed forest habitats and a low tolerance for habitat degradation and fragmentation. Until shown otherwise, it should be assumed that populations of K. muscina will persist only in relatively intact forest habitat.

Nothing is known of the feeding ecology or reproductive biology of the species but it is probably similar to other species of Kerivoula. Its morphology suggests that it is a slow-flying ‘foliage gleaner’, adapted to foraging in dense vegetation. The only information on roost location comes from discovery of a group of three K. muscina inside a curled banana leaf (Flannery and Seri 1990). Other species of Kerivoula have been observed to roost singly or in small groups in tree hollows, epiphytes or abandoned bird nests.

This species is endemic to the main island of New Guinea where it has been recorded from several widely distributed sites. All known occurrences are in Papua New Guinea but it is very likely present in parts of Papua Province, Indonesia, although this requires confirmation. It ranges from sea level to 1,600 m Asl, but is probably predominantly a lowland species.

It has been recorded from Varirata National Park, Central Province in Papua New Guinea (Flannery 1995).