Sinharaja mixed-species bird flocks (bird waves): nuclear species and foraging synergy?

The mixed-species bird flocks (bird waves) of Sinharaja Rainforest are among the largest and most complex documented in global ornithology, averaging 12 species and over 40 individuals moving together through the canopy. The flock centers on "nuclear species": the endemic Orange-billed Babbler (Turdoides rufescens), which travels in noisy family groups through mid-story foliage, flushing flying insects, and the Greater Racket-tailed Drongo (Dicrurus paradiseus lophorinus), which flies along the perimeter acting as a sentinel. Attendant species—including the Sri Lanka Blue Magpie, Malabar Trogon, and Red-faced Malkoha—join the wave to feed on escaping insects while benefiting from drongo predator alarm calls.