It breeds colonially in the crevices of rocky cliffs and deep gorges, at 200-2,470 m, generally in the vicinity of forest. Breeding is from March to May usually at the same site each year (Chantler and Kirwan 2020). Birds apparently remain in close proximity to the nesting colonies while breeding, normally disappearing soon afterwards and reappearing the following year. Away from breeding sites, it has been recorded up to at least 1,500 m. It has been suggested that it may only undertake local movements, but this requires further investigation.

Apus acuticauda is known from just a few breeding colonies in the Himalayan foothills of Bhutan and north-east India (BirdLife International 2001, Chantler 2005, Ahmed et al. 2007, K. D. Bishop in litt. 2013, J. Eaton in litt. 2013, M. Sharma in litt. 2013, Choudhury 2013). There are year-round records from various parts of India and Myanmar, along with previous records from north-western Thailand where may be vagrant, though status here is unclear (Chantler and Kirwan 2020, eBird 2024). Its seasonal movements and wintering areas are virtually unknown. 

Conservation Actions Underway
A presumed breeding site is located within the Blue Mountain National Park, Mizoram, north-eastern India. Strict forest policy and wildlife protection laws in Bhutan suggest that its future there is secure.

Conservation Actions Proposed
Encourage surveys for this species across north-eastern India, Bhutan, northern and western Myanmar, Thailand, Laos, Viet Nam and Cambodia to establish its breeding range and population status. Research its ecology and seasonal movements. Investigate potential threats. Afford strict protection to all known colonies.