Table 4 Summary of the experimental schemes of predator presentation experiments and the equipment used in the recording of the vocalizations. The microphone type rather than the audio recorder model may affect the representation of frequencies in the recording. Therefore, we marked the microphone type in bold here to indicate the differences in recording equipment. This is also associated with either using a natural snake or plastic snake in the tests; as the natural snake movements during a test were less consistent across the tests than the imitated movements of the plastic snake we expect that variation among tests might have been larger for tests with natural snakes (hence, in experiments recorded using Sennheiser ME67). This determined the method of statistical comparisons of acoustic properties of ‘L’ phrases in the Oriental tit. Only the comparisons within the same microphone type were conducted. More details are in Supplementary Table S7.

From: Unlearned adaptive responses to heterospecific referential alarm calls in two bird species from separate evolutionary lineages