The Indian subcontinent is a major wintering area for many migrant birds from Central Asia and Russia and has experienced unprecedented landscape changes over the last two decades. The effects of these changes on the population of bird communities, especially on raptors, are unknown or poorly assessed. Migrant harriers Circus spp. that require large open grassland, savannahs or sparse scrubland to roost and forage in their wintering quarters, have become scarce in recent times. The species composition and abundance of harriers at historically documented roost sites, when monitored across years, can provide valuable information on their demographic status since data from their possible breeding locations in Russia is not readily available. Here, we collate published and unpublished information on various harrier roosts using predefined protocols to assess trends in the counts of harriers in protected and unprotected sites across the Indian subcontinent. Harrier counts across all sites, both protected and unprotected, showed a declining trend over the period 1985–2015. Limited species-specific data from two sites show a significant decline in Western Marsh Harrier Circus aeruginosus but not in Pallid Harrier C. macrourus and Montagu’s Harrier C. pygargus. These may be early signs of population declines at a continental scale, and we urge the development of more robust systematic ways, along with the current method, to monitor harrier populations. There is a need for improvement of international collaborations with researchers in the breeding areas to conduct studies on long range migrants and to set up a national conservation plan to protects harriers and grasslands.