Intern Adventures: Timing is Everything — Early Bird in the Field Spots Rare Cuckoo

By Thomas Serrano, Pathways Intern, Pacific Region of the U.S. Fish and Wildlife Service

The sunrise on the beautiful Snake River in Idaho. USFWS photo: Thomas Serrano

After waking up at 4:00 a.m. to an unwelcomed alarm, I grabbed my coffee, jumped in my truck, and headed out for a day of fieldwork. A beautiful Idaho morning was dawning as I pulled into the dirt parking lot, to meet U.S. Fish and Wildlife Service biologists Katie Powell and Jaan Kolts. Surrounded by nothing but farmland and cattle, our objective for the day was straightforward — find the elusive, threatened, yellow-billed cuckoo. Simple? Yes. Easy? No.

The yellow-billed cuckoo is a neotropical migrant, meaning it migrates to South America during the winter and breeds in North America during the summers. They are flashy birds with a bright white breast, long spotted tails, and a distinctive down-curved, yellow bill. Cuckoos in the West need healthy, riparian corridors full of mature cottonwoods. They rely on a complex understory of willows and shrubs that provide plenty of forage, especially caterpillars.

A yellow-billed cuckoo can be seen close-up on a branch. The belly is white, and the wing and head are gray. The yellow beak can also be seen.
The yellow-billed cuckoo is a flashy bird with a white breast and distinctive, down-curved yellow bill. USFWS photo

Unfortunately, the western distinct population segment of yellow-billed cuckoo has been declining in the past few decades due to altered river and stream flows, drastic habitat alterations, and conversions from riparian forests to housing and farmland. Idaho is at the northern limit of its range and, although there are small breeding populations in eastern Idaho, the last known sighting in this survey area was in 2014. Due to these declines throughout the West, the western distinct population segment was listed under the Endangered Species Act as threatened in 2014.

Just a few weeks prior to our fieldtrip, during their initial survey this year, Katie and Jaan made an exciting discovery — an unexpected and exciting cuckoo detection! Our goal today was to determine if the bird was still in the area and maybe discover its breeding status.

Still waiting in the parking lot, I perked up as I heard the hum of their large SUV with the forest green canoe strapped to the roof. After parking my truck in the staging area, we drove upstream to deploy into the river. Katie and Jaan, both significantly more awake than I was, gave a quick briefing on safety and survey protocol as I swatted mosquitoes torturing my neck.

As a New Mexico native, I have limited experience with watercraft. I crouched down in the center of the boat, trying my best not to flip the wobbly canoe. Finally, after a last-minute checklist to ensure we didn’t leave anything critical in the car, Jaan jumped in and pushed us from the river bank. As the passenger not burdened with paddling the canoe, my job was to navigate us to each survey point using an archaic GPS that was not at all intuitive to my Gen Z mind.

Katie, Thomas, and Jaan are all smiles as they conduct yellow-billed cuckoo surveys in a canoe. USFWS photos: Katie Powell

Luckily, Jaan has a good memory.

Katie aimed our canoe to the shore of our first survey point, which we narrowly missed as the river pulled us downstream. We semi-crashed into the shore, drug the canoe upslope, and sat in silence, allowing ourselves to acclimate to the soundscape. Katie pulled out a large speaker, called a Foxpro, from her bag, and began broadcasting a series of loud ka’s and kwolp’s — the cuckoo’s mating song. We sat again in silence, listening and scanning the treetops for a flash of their white breast or long tail. Nothing. I was grateful to return to the water again to escape the evil mosquitoes.

We continued this process, going from point to point, doing our best to park the canoe in the right spot, and trying not to flip on the mini rapids. Finally, we got to our third point. Katie and Jaan were cautiously optimistic because this point was near their last sighting. Katie held up the Foxpro, and we waited. She suddenly whispers “cuckoo” and excitedly points to a bird diving into a large cottonwood tree.

Jaan, who also jumped, immediately had his binoculars trailing the bird into the tree and excitedly confirmed the identification.

Unfortunately, I missed it, but Jaan quickly guided me to it. There, barely distinguishable from the cottonwood’s pale bark was a bright white breast and a glimpse of a yellow bill. We had found it! It sat there, softly cooing, and then called out its distinctive series of ka’s and kwolp’s. Jaan and Katie’s enthusiasm was contagious, and I was so excited to be part of this long-awaited observation!

We didn’t stay long as we didn’t want to overstress the bird. We got back in the canoe and excitedly discussed the implications of this discovery. The fact that we had an additional positive detection, indicated it may be nesting in the area!

We skipped our following points so as not to lure the same bird and floated further down the mighty Snake River. Well, less mighty these days, as the river was so shallow in some parts, Katie or Jaan had to get out and drag the canoe over the gravel as we traversed the river to the other side. We lodged ourselves in the muddy bank and began what was now routine– sitting in silence while the call was played.

This time, Jaan excitedly pointed at a silhouette with a strikingly long tail flying across the river and perched in a cottonwood. I could barely find the bird through the foliage. Still, soon, it made its distinctive mating call, confirming what we had suspected — another cuckoo. This bird was likely not the original one we saw because, at this point, we were over a kilometer away from our first sighting. After close to 10 years, yellow-billed cuckoos were once again confirmed in Southwestern Idaho.

Pockets of cottonwood trees, the yellow-billed cuckoo’s preferred breeding habitat, can be seen under a beautiful sunrise. USFWS photo: Thomas Serrano

This survey was a highlight of my summer pathways internship with the Idaho Fish and Wildlife Office. It was a day of learning and adventure while contributing to cuckoo history. After we loaded up the canoe, still early in the morning, I returned home for a much-needed nap, glad to have a deep sleep without the anticipation of my alarm’s “cuckoo.”



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USFWS Columbia Pacific Northwest Region

USFWS Columbia Pacific Northwest Region

Conservation stories from one of the world’s most ecologically diverse regions.