Long distance migration of birds, like other natural seasonal phenomena, is affected by environmental factors such as temperature and precipitation. Significant changes in migratory patterns have been documented for many bird species in various parts of the world and these have often been attributed to climate change. Documenting and understanding such changes is important because these may have significant implications for the survival of migratory species. Unfortunately, hardly any detailed information is available on the timing of bird migration in India, and how this might be changing. Information collected in MigrantWatch will add to the global understanding of the effects of climate change on phenology (the timing of natural events).