An endangered bird calls less when invasive birds are calling

Novel noises can affect various animal behaviours, and changes to vocal behaviour are some of the most documented. The calls of invasive species are an important source of novel noise, yet their effects on native species are poorly understood. We examined the effects of invasive bird calls on the vocal activity of an endangered Australian finch to investigate whether: (i) native finch calling behaviour was affected by novel invasive bird calls, and (ii) the calls of the finches overlapped in frequency with those of invasive birds. We exposed a wild population of Black-throated Finch southern subspecies (Poephila cincta cincta) to the vocalisations of two invasive birds, Nutmeg Mannikins (Lonchura punctulata) and Common Mynas (Acridotheres tristis), a synthetic ‘pink’ noise, and a silent control. To determine whether the amount of Black-throated Finch calling differed in response to treatments, we recorded and quantified Black-throated Finch vocalisations, and assessed the amount of call...