Innovative microphone transmitter reveals differences in acoustic structure between broadcast and whisper songs of Myadestes obscurus (ʻŌmaʻo)

Low-amplitude ‘whisper songs’ are a taxonomically broad phenomenon in birds that could play an important role in the suite of behaviors birds use to communicate. Due to its cryptic nature, there are inherent difficulties in capturing high-quality whisper song recordings without interrupting natural behaviors. Thus, whisper song acoustic structure is poorly understood and its potential function remains the subject of debate. Here, we present one of the first quantitative assessments of the acoustic structure of whisper song in birds. Using an innovative microphone transmitter we collected high quality recordings of broadcast and whisper songs from the Myadestes obscurus (ʻŌmaʻo), a thrush species endemic to the Island of Hawai‘i. The transmitter was attached to the birds and broadcasted radio-signals of all vocalizations produced by the individual to distances over 100 m away which minimized disruption of the birds’ normal behavior while recording. We demonstrate that ʻŌmaʻo whisper song..., We equipped ʻŌmaʻo with a device that consisted of a very high frequency (VHF) radio pulse transmitter and a miniature condenser microphone that broadcasted all sounds emitted by the target bird (JDJC Corporation, Fisher, IL, USA). Radio signals from the microphone transmitter were received by a hand-held 3-element yagi antenna (JDJC Corporation, Fisher, IL, USA) connected to a wideband receiver (AR8200; AOR Ltd., Tokyo, Japan) in wideband amplitude modulation (WAM) mode. The signals were recorded by a Marantz PMD661 professional field recorder (Marantz America, LLC., Mahwah, NJ, USA), using a 2-second pre-record setting, as 24-bit WAV files at a 44.1 kHz sampling rate. The distance at which the microphone transmitter could be detected varied by terrain and weather, and birds recorded in our study were typically at a distance of < 80 m. Each bird was tracked 3–5 days a week, excluding rainy days, for 2–4 hours between 0800–1600, which encompasses the peak hours for ʻŌmaʻo vocalizatio..., , # Data from: Innovative microphone transmitter reveals differences in acoustic structure between broadcast and whisper songs of Myadestes obscurus (ʻŌmaʻo)

[https://doi.org/10.5061/dryad.kd51c5bgg](https://doi.org/10.5061/dryad.kd51c5bgg)

## Description of the data and file structure

### Files and variables

#### File: OMAO.Whisper.Songs.DB.luscdb.zip

**Description:** Luscinia formatted database files for the whisper songs collected during this study. The files can be opened and analyzed using Luscinia bioacoustic software by unzipping the file, opening Luscinia, then navigating the \"Database location:\" search box on the Log In page to the directory containing the OMAO.Whisper.Songs.DB.h2.db and OMAO.Whisper.Songs.DB.trace.db files (described below). It is important to navigate to the parent directory, and not the database files themselves, as they will not open independently. 

##### Subfile: OMAO.Whisper.Songs.DB.h2.db

**Description:** Whisper song recording database formatted fo...