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“Not adjacent clip for birds to alert to confederate skies.” That is simply a enactment from Stevie Wonder’s “I Just Called To Say I Love You”, a opus that has stood the shifting fads of time. And that enactment refers to an avian signifier that has persisted done time. It hints astatine birds migrating from the north, escaping its inclement wintertime to sojourn successful the south. While the flight volition proceed wintertime aft winter, the sojourn tin acquisition changes of address, depending connected section factors, anthropogenic and climatic.
Welcome to the choices made by migratory birds: the however and wherefore of it.
Dr. T. Badri Narayanan is an ophthalmologist with an oculus for birds, an oculus sharpened with immoderate grade of ceremonial grooming (a correspondence people from Bombay Natural History Society and an ornithology people offered by NPTEL during the pandemic) but mostly connected relationship of clip spent connected the field. He illustrates the imaginable causes of alteration successful vertebrate migration with his observations of the Common pochard successful the Chennai Metropolitan Area and his regular stomping ground, Madurai.
Dr. Narayanan notes that the migratory Common pochard is sighted sporadically successful the Chennai Metropolitan Area which includes patches of Kancheepuram and Chengalpet. It is besides documented from clip to clip successful different parts of confederate Tamil Nadu. He recalls sightings of Common pochard flocks astir 15 years agone astatine Aarpakkam vessel adjacent Kancheepuram arsenic good arsenic Ponnur lake, besides acceptable successful the aforesaid geography. During the 2025-26 migratory season, the Common pochard showed up arsenic a flock astatine Amoor lake, adjacent Sirudhavur successful Chengalpet district, not excessively acold from Chennai.
In contrast, birders successful Madurai are being stood up by this bird. For anyone who has birded successful the 1980s and 90s, this could beryllium startling arsenic Madurai was a sure-fire destination successful this bird’s wintertime itinerary. Dr. Badri Narayanan notes that a taxon tin alteration its wintering code if it is up against situation degradation. The world successful Madurai does not constituent successful that direction, astatine slightest not connected the surface, and helium looks elsewhere for a imaginable cause.
He observes that globally, the Common pochard’s numbers are dwindling and the taxon has moved from “Least Concern” to “Near Threatened”, and therefore, less birds migrate heavy into peninsular India. The proposition is that they could beryllium happily “hot-desked” with capable “seats” provided for them successful the wetlands of cardinal and bluish India.
A migratory vertebrate mightiness alteration its wintering code for 1 oregon a operation of these reasons. One, situation destruction. Two, nutrient scarcity. Three, climatic changes. Four, colonisation diminution reducing migratory dispersed (the Common pochard’s concern successful Madurai astir apt checks this box). Five, availability of suitable habitats earlier connected successful their migratory route. Dr. Badri Narayanan notes that a origin tin beryllium identified lone with capable information gathered implicit a agelong play of clip with observations, astir 10 years oregon more. He points retired that citizen-science platforms specified arsenic eBird tin beryllium root for that benignant of data.
