Introduction

The Merlin App often lists birds that I do not hear. Also, when recordings from Merlin are played back using WASPS I see events on the spectrograph that I cannot here. Merlin gives the time in the recording that a species is first identified. I wondered if I could correlate the events I see on the spectrograph with the birds Merlin is identifying.

Methods

I started a recording using the Merlin app on my cell phone. I then placed my cell phone on a log and walked away. As I was walking I could hear some birds but could only pick out a few. There was also a dog barking in the neighborhood. I returned about five and a half minutes later, retreived my cell phone, and stopped the recording.

Merlin reported 11 species of birds

Tufted Titmouse @ 00:06
American Crow @ 00:28
Northern Cardinal @ 01:04
Wild Turkey * @ 01:05
White-thoated Sparrow @ 01:35
Red-bellied Woodpecker @ 01:47
Blue Jay @ 02:40
Red-tailed Hawk @ 02:41
Carolina Wren @ 03:08
Carolina Chickadee @ 03:58
Song Sparrow @ 03:50

I know I did not hear all of these birds while walking.

At home, I played back the recording using the Merlin app. I could discern the following by ear.

Tufted Titmouse
American Crow
Blue Jay
Dog barking
Red-tailed Hawk
Red-bellied Woodpecker
Unidentified bird

There were some signals on the recording that I could see on the audio spectrograph but could not hear.
There were also some signals discernable on the recording but burried in the ambient noise generated by my walking away and returning.

I then conected my cell phone to my computer and opened the file using the WASP app. The WASP app permitted me to select portions of the spectrograph for detailed study. I immediately went to the time in the recording where the wild turkey was first identified and found that it was actually the barking dog. I could also associate other signals on the spectrograph with different birds Merlin had identified; both those I could here and those I could not hear.

I think I will start to include spectrograms with my iNaturalist observations.

Posted on October 16, 2024 02:27 PM by frank879