Chinese Blackbirds (Turdus mandarinus) mimic electric moped sounds with lower consistency and frequencies

Abstract

Passerine mimics often imitate various vocalizations from other bird species and incorporate these sounds into their song repertoires. While a few anecdotes reported that wild songbirds imitated human-associated sounds, besides captive parrots and songbirds, systemic and quantitative studies on human-made sound mimicry in wild birds remain scarce. In this study, we investigated the mimetic accuracy and consistency of electric moped sounds imitated by an urban bird, the Chinese Blackbird (Turdus mandarinus). We found that: (1) Only one type of electric moped sound was imitated, i.e., 13 of 26 males mimicked the first part of the antitheft alarm, a phrase containing a series of identical notes. (2) The mimicry produced by male Chinese Blackbirds had fewer notes and lower consistency within phrases compared to the model alarms. (3) The mimicry of male Chinese Blackbirds was imperfect, i.e., most of the acoustic parameters differed from the model alarms. Additionally, mimetic notes were lower in frequency than the models. Mimetic notes from two areas were also different in acoustic structures, suggesting Chinese Blackbirds might learn mimicry mainly from conspecific neighbors within each area respectively rather than electric mopeds, namely the secondary mimicry. Imperfect mimicry of human-made sounds could result from cost and physical constraints, associated with high consistency, frequency, and repetitions. Consequently, Chinese Blackbirds copied a simplified version of electric moped alarms. We recommend further attention to mimic species inhabiting urban ecosystems to better understand vocal mimicry's adaptation to ongoing urbanization.