Song thrush thrush recognizes the cuckoo's non-mimetic eggs. However, the song thrush does not demonstrate the same aggression toward the adult cuckoo that is shown by the blackbird. The introduced birds in New Zealand, where the cuckoo does not occur, have, over the past 130 years, retained the ability to recognise and reject non-mimetic eggs. Adult birds may be killed by cats, little owls and sparrowhawks, and eggs and nestlings are taken by magpies, jays, and, where present, grey squirrels. As with other passerine birds, parasites are common, and include endoparasites, such as the nematode "Splendidofilaria (Avifilaria) mavis" whose specific name "mavis"
Bicknell's thrush 90% of the individuals wintering in Hispaniola. During the winter, they live in broadleaf forests at various elevations but generally preferring higher elevations. Vocalizing mostly at dawn and dusk, the song is mostly performed by the male, but sometimes also by females. Like all North American thrushes, Bicknell’s thrush song is flute-like. High pitched and vibrant, the song is composed of four phrases: “"chook-chook, wee-o, wee-o, wee-o-ti-t-ter-ee"”. Unlike in Gray-cheeked Thrush, the pitch of the last phrase is constant or rising. Primary call is a downward whistle named the “Beer call” “"beer”". Other calls include growl call given in alarm