Onset of early summer has triggered early return of migratory birds from the region.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/migratory-birds-prepare-early-return-temperatures-soar
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/times-india-new-delhi
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/uttar-pradesh
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/global-warming
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/migratory-species
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/birds
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ganga
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/climate-change