The intricate nesting habits of Baya Weaver Ploceus philippinus were studied on two Palmyrah Palm Borassus flabellifer trees in Chendur village, Villupuram district, Tamil Nadu between 20 March and 30 November 2020. Observations concentrated on sources of fibers, developmental stages of nests, re-construction & repairing of nests, deposition of clay in the nest walls, and various threats. A total of 98 nests of various developmental stages (wad stage—4, helmet stage—31, egg-chamber closed stage—5, and complete nests—58) were studied on these two nest colonies. The birds used leaf fibers of Indian date Palm Phoenix sylvestris and Sugarcane Saccharum officinarum as nest materials, and took 6–48 days for construction of a complete nest. 95% of helmet stage nests (n = 126) contained clay deposits. Analysis of plastered clay revealed it was alkaline with pH 9, and dry weight ranged from 5.1–5.8 g. Males re-constructed new nests from the remnant stalks attached to tips of palm fronds, and also made repairs on damaged nests. Anthropogenic factors, wind, rain, and avian predators, such as House Crow Corvus splendens, Long-billed Crow Corvus macrorhynchos, Rufous Treepie Dendocitta vagabunda, and Shikra Accipeter badius posed threats to Baya Weavers. A total of 42 nests, 11 broken eggs, and 14 dead chicks were found fallen under the two supporting trees. The detailed systematic survey covering entire district, rapid urbanization, and the anthropogenic pressures will help in nest drafting an action plan to conserve local populations of Baya Weaver.