Standardizing Vocalization Types of Black-billed Cuckoos

Vocalization patterns in black-billed cuckoos (Coccyzus erythropthalmus) remain understudied. This project aims to standardize their vocalization types by identifying and categorizing distinct call types, along with key spectral features such as frequency, duration, and entropy, to create a consistent vocal repertoire for the species. A bird’s vocal repertoire refers to the full collection of sounds it produces, including both songs and calls. I analyzed existing audio recordings from Xeno-Canto, focusing on the two primary call types of the black-billed cuckoo: the “cadence coo” and the “rattle.” The goal was to establish a standardized framework for describing these vocalizations and to clearly define the distinguishing characteristics of each call type. Through this analysis, I found that modulation index, median time, and entropy were the three most influential spectral properties separating cadence coos from rattles. Modulation index reflects the variation in frequency over time; entropy measures how tonal or noisy a call is, with higher entropy indicating greater acoustic complexity; and median time identifies when the midpoint of the call’s energy occurs, helping describe its temporal structure. By examining the relationships between these properties, I was able to reliably differentiate between the two call types. Standardizing these vocalizations supports passive acoustic monitoring—a non-invasive and increasingly vital method for avian population surveys. Additionally, the methodology developed here can be adapted to other species, contributing to broader research in soundscape ecology and enhancing acoustic survey techniques.