by Big Sky Watershed Corps member Peter Dudley

Black-billed Cuckoo – Photo Courtesy Bo Crees

Montana Audubon was back on the Missouri and Madison Rivers for Black-billed Cuckoo and avian surveys this summer, after a great pilot year in 2020. For nearly a decade, we have carried out land bird monitoring in partnership with the University of Montana Bird Ecology Lab (UMBEL) Montana, Fish & Wildlife and Parks (FWP), and the Bureau of Land Management (BLM). Every year we try to both refine the project and increase it’s scope in order to gain a better understanding of Black-billed Cuckoo, as well as other species, and their distribution in the state.

A new tool, Automated Recording Units (ARUs,) were used this summer. The ARUs, microphones that periodically record throughout the day, can record cuckoos from up to 150 meters away. That audio data is then run through a program trained to detect cuckoo calls within the audio recordings. With 43 of the 44 ARUs along the Missouri River retrieved (we think someone ran off with one of the units,) we expect to gain a much better understanding of cuckoo populations in Montana.

Along with the ARUs, Montana Audubon staff and research technicians set out to conduct our riparian bird surveys and “call-back” surveys in late-May. At each survey point, we conduct a 10 minute bird survey followed by a vegetation assessment. Black-billed Cuckoos are very territorial birds, so if they are present anywhere within hearing distance of our playback, they typically respond and make themselves known very quickly.

Although results from our ARU’s won’t be available until later this fall, the season is already a success. We found two Black-billed Cuckoos at the end of our first multi-day survey float on the Missouri River and five on another multi-day survey. It will be even more interesting to see how many ARU’s will actually capture the calls of this unique species in areas where we did not detect Cuckoos in person. Now we just have to be patient and hope our data was well-recorded.

 For a full report go to: