About this time last year, we put out an Autonomous Recording Unit (ARU) in a remote cove near a man-made floating nesting platform to try to capture vocalizations of the Common Loon. With a special Research Permit from Acadia National Park, and the help of Billy Helprin, Director of the Somes-Meynell Wildlife Sanctuary (they run the MDI Loon Monitoring Project), the ARU was set to record from sunset thru the early morning. With any luck, we’d hoped to to hear wails, tremolos, yodels, and hoots. And if we were really lucky we thought we might even hear young loons “purring”.
Soon after placing the ARUs nearby, a pair nested on the floating platform, but by mid-June, it was clear from reports of volunteer observers that the loons were no longer on the nest. We weren’t sure what happened but we realized that while it was a little late in the season to begin nesting, they, or another pair might try anyway. So we went out to the site again, removed the single ARU we had set up in May, and this time set out several ARUs to run 24/7 until early August.
We have not fully processed and analyzed the 2022 recordings but a quick look at the early recordings proved 1) we could get very good recordings with ARUs near the nest site (here’s one) and 2) that our decision to deploy more ARUS at the site, and this time run them 24/7, in case a pair tried to nest there again was a good idea. Because, as we learned later, we had actually captured the event of the Loon’s nest being predated upon! We had set the timer on the first ARU to shut off at 8am, since the majority of most vocalizations are evenings and early mornings. In a recording of the morning of June 12th, we heard the loons “screaming” in distress and splashing violently, and what we thought sounded like what might be a mammal grunt … and then right in the middle of the “attack” the timer shut down the ARU at 8am as it had been programmed. And, the same pair of loons did nest again! And they had one chick that survived the season, and flew away very late in the season. We’re looking forward to listening and sharing any results with you, a little at a time, over the coming months. We’re hoping for a more complete story of the this pair’s 2022 nesting season as told in their own voices.
Meanwhile, this past weekend, we set up 8 ARUs to record 24/7 and sequenced to each record for about 2+ weeks from now till mid-September. Fingers crossed again!