Great Cormorants Nesting

This spring great cormorants (カワウ) are nesting high in trees along Yasugawa near my home in Ritto City, Shiga Prefecture, Japan. On Saturday, April 21, 2018, I made an audio recording in the woods under their nests. I tried to minimize sounds of human activity by recording during lunchtime.

Audio recording was done under the nests, where white bird poop covered everything. The cleanest spot was right at the trunk of a large tree.

At that location it was hard to see the birds in the dense woods.

They are more visible along a nearby dirt road.

Great cormorant (カワウ)

Great cormorant (カワウ) in Hayashi, Ritto City

Great cormorant (カワウ)

Great cormorants (カワウ) in Hayashi, Ritto City

Great egrets are also nesting nearby. I could hear the sounds of their wings as they landed on treetops. Sometimes I could see one overhead.

Great egret (ダイサギ)

Great egret (ダイサギ) in Hayashi, Ritto City

I saw one broken egg, but obvious signs of death are rare here in the woods.

Broken great egret egg

Broken great egret egg in the woods in Hayashi, Ritto City

Soon quite a few young people will be swimming and playing in the river just a few hundred meters downstream. Probably they’ll be unaware of the colony of great cormorants nearby.

Great cormorants (カワウ)

Great cormorants (カワウ) along Yasugawa in Yasu City, seen from Hayashi, Ritto City

Recording and post-processing

This method of quasi-binaural recording attempts to emulate human perception by placing left and right omnidirectional mics on either side of an object about the diameter of a human adult head. It is not ideal, of course, but setup can be done very quickly.

This recording was made with a Sony PCM-M10 recorder and FEL Communications Clippy Stereo EM172 Microphone tied to a tree. Since the tree was quite a bit larger than a human head, I placed the mics placed forward of center facing toward the river and away from a nearby dirt road.

Audio post-processing was done with Audacity on Fedora Workstation, a Linux system running on a Lenovo ThinkStation 20 computer. I trimmed this excerpt from a longer recording, raised the overall volume, and added fade-in and fade-out. No other digital signal processing was done.

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