Audio Recording Device Data for Assessing Avian Detectability, Seward Peninsula, Alaska, 2013-2014

We deployed one Song Meter digital recorder at each site (Model SM2, Wildlife Acoustics, Maynard, Massachusetts, USA), set to record for 10 min at the start of every hour in 2013 and every other hour in 2014. We deployed recorders as early as possible in late spring and left them in place for the duration of the breeding season. Recorders were attached to stationary metal poles at a height of 1 m above the ground. At one site, we attached the recorder to the bole of a small spruce (Picea sp.) tree at a height of 1.5 m. All recorders were placed ≥1 m from tall deciduous vegetation to reduce interference from rustling leaves. We attached foam covers to microphones to reduce the impact of wind and rain on the recordings. Rain in our study area tended to be light and misty and did not interfere heavily with recordings (S. T. Vold, U.S. Geological Survey, personal communication). Recorders were visited infrequently, 1–4 times per season, to check device functioning and change batteries and memory cards. Most recorders were co-located with HOBO weather monitoring devices (Onset Computer Corporation, Bourne, Massachusetts, USA). Three sites had HOBO U30 weather stations (all in 2014), which measured wind speed and direction, relative humidity, and temperature, and six sites had HOBO Pendant units (model UA-002-08) that measured temperature and light intensity (two sites in 2013 and four in 2014). We set weather monitors to record weather data every 30 min throughout the day for the duration of the audio recording period. For analysis, we selected the weather measurement taken at the time closest to the beginning of the 10-min audio recording. If there was not a weather recording within 1 hr of the start of the recording, we did not associate weather data with the recording.