Skip to Main Content
Mobile Menu


cover pic

Yellow Warblers Love the Boise River: A High School Student Investigates

For the past few months, Sage International School senior, Zoe Daly has been working on a project using Yellow Warbler data from the Intermountain Bird Observatory’s Boise River Research Station.

A Yellow Warbler is weighed at our Boise River Site, just before being released. Photo by Tom Carroll

A Yellow Warbler is weighed at our Boise River Site, just before being released. Photo by Tom Carroll

In the Fall of 2017 IBO ran nets daily during fall migration for the first time ever! This gave us an excellent, fine-scale picture of migration at the river station. We were also able to complete a full MAPS breeding season banding protocol this summer, sampling songbirds at the site once every 10 days. Simultaneously, we collected the same data at our long-standing Lucky Peak station.

This gave us the ability to compare between our Boise River and Lucky Peak stations like never before.

When we first started banding at the Boise River site, we knew that it was special for Yellow Warblers (we once caught more than 200 of them in a single day!) but we had never looked at the hard data or quantified exactly what was going on. So, when Zoe came along and told us she loved looking at data and graphs, we knew exactly what she should do.

The Cottonwood overstory and thick willow, currant, and rose shrub layer at our Boise River Site is ideal habitat for Yellow Warblers.

The cottonwood overstory and thick willow, currant, and rose shrub layer at our Boise River Site is ideal habitat for Yellow Warblers. Photo by Tom Carroll

Zoe took our banding data from Lucky Peak and the Boise River and compared Yellow Warblers at both sites. In particular, she looked at the fat levels of Yellow Warblers.

She found that Yellow Warblers were significantly fatter at our Boise River Station than at Lucky Peak.

This means that the habitat at the Boise River provides food that Yellow Warblers need during migration and stopover. They are able to spend time at the site, eat, and “fuel up” with fat for the next leg of their migration journey.

Zoe also found that Yellow Warblers at Lucky Peak tend to leave the area soon after their young fledge…they don’t stay at the site during late summer when migrants begin fattening up. Instead, they seem to travel to the river to finish molting and fattening up for migration.

This goes to show that the riparian habitat at the Boise River is a key resource for neotropical migrants like Yellow Warblers.

Congratulations to Zoe for completing this poster and finding such interesting results! Thanks also to Guy Falconer of Sage International School who connected Zoe with IBO to begin this internship.

Check out Zoe’s full poster to learn more:Poster showing graphs of Yellow Warbler fat levels. Yellow Warblers were fatter at the Boise River than at Lucky Peak

(full size poster PDF available here)

Project WAfLS commences!

Project WAfLS 2018 has begun! Find out how you can become a citizen scientist and help us learn more about Short-eared Owls. This year we’re accepting volunteers in UT, ID, MT, CA, WY, NV, WA and OR!

Visit the official website for more information:

Short-eared Owl on a fencepost

Short-eared Owl by Becky Lyle

How can YOU make a significant impact towards conservation?

We want to express our heartfelt thanks for all the donations and support we’ve received to date. Thank YOU for your continued generosity!

With the end of the year fast approaching, IBO needs your help to support some of our most iconic projects.  Don’t forget to make your gift prior to Dec. 31 to receive tax benefits.  Your gift to the Intermountain Bird Observatory may also qualify for an additional education tax credit in Idaho.

While research grant budgets continue to expand each year, securing support for our annual fall migration project at Lucky Peak continues to be a challenge.  A little known fact is that the fall project has been almost entirely supported by individual private donations for the past several years now. We need your help to make sure this project will continue!

Other major IBO projects also need support:

Boise River site

Song Sparrow--Photo by Bryce Robinson

In 2017 we had enough donations saved up to run a fall banding project, reaching over 600 Treasure Valley Students. But, we don’t have enough funding to repeat this project in fall 2018. Plans to build an education program endowment would ensure that our education and outreach efforts at the Boise River site and at Lucky Peak would continue indefinitely.

Hummingbird banding

Photo by Liz Urban

Another favorite: hummingbird banding at our Idaho City location, is also sorely underfunded.  This favorite activity among IBO supporters hosts hundreds of people each year to observe and participate in this most special of opportunities.


Gorongosa National Park

Photo by John Kelly


Our efforts in Mozambique at Gorongosa National Park would greatly benefit from your generosity-please assist us in tracking endangered vultures or supporting Mozambican interns.


And don’t forget that we always appreciate your in-kind donations of much needed items for our various field projects such as 4×4 vehicles in good working condition, ORV’s such as 4-wheelers, camping equipment for trainees, wall tents and accessories, and optics such as binoculars, spotting scopes, and tripods.  Our Mozambican Trainees, not used to chilly fall conditions in the temperate zone, would really appreciate your lightly used winter clothing!

There are two easy ways to support the Intermountain Bird Observatory:

Or, you can mail a check payable to:

Intermountain Bird Observatory c/o BSU Foundation, Inc.
1173 W University Drive
Boise, ID 83706

Please specify if you wish for your donation to go towards a specific project, e.g., Hummingbirds, Lucky Peak, Long-billed Curlews, otherwise it will go into the general IBO account.

For additional questions on supporting IBO, please contact Jim Ogle at 208-426-3230 or

A Gift in Your Will or Living Trust – the Easiest Way to Make an Impact

Interested in helping the Intermountain Bird Observatory contribute to conservation efforts that directly impact human lives? A simple and versatile way to ensure that we are able to conduct our research focusing on migratory birds, education, discovery of the natural world, and community engagement is with a gift in your will or living trust.

By including a bequest to the Boise State University Foundation, specifically for the IBO, you are ensuring that we can continue our work for years to come. As little as one sentence in your will or living trust is all that is needed to complete your gift.  If you’d like to learn more, please contact our Executive Director of Gift Planning, Jennifer Neil at

 Happy Holidays!!

Ecotourism in Southern Africa

In 2014, IBO formed a partnership with the Gorongosa Restoration Project, which in ~3 short years already includes IBO’s research on vultures and other raptors as well as mentoring young Mozambican scientists. Since the start of this partnership we’ve had a goal of helping boost American ecotourism to Gorongosa National Park in Mozambique.

endangered southern ground hornbill

Gorongosa is home to many endangered and threatened bird species, such as this Southern Ground Hornbill, seen on our 2017 Ecotour to the park.

Mozambique, and Gorongosa in particular, has great bird diversity and a number of species hard to see elsewhere in southern Africa but is off the beaten path due to decades of political conflict – some of which centered on the park itself – and being one of the poorest countries in the world. However, the last decade has witnessed the recovery of many of the wildlife species in Gorongosa while the park and restoration project seek to build sustainable human communities around the park.

three lion cubs in Gorongosa National Park

These three healthy lion cubs were one of many signs we saw that Gorongosa’s wildlife is recovering

Jay worked with Alastair Kilpin of Mammoth Safaris to build an itinerary rich with mammal and bird diversity to provide a potential “once-in-a-lifetime” trip to Africa. We settled upon a 15-day itinerary with 3 main destinations in Mozambique and South Africa – Gorongosa National Park, Kruger National Park (Private Reserves), and Cape Town – with single-day excursions to Johannesburg and Dullstroom in South Africa and Beira, Mozambique. Our group of enthusiastic travelers meshed very well and were fun to explore with. We also really enjoyed working with Alastair – a great birder and safari guide who was easy to work and travel with – and the many talented local guides that helped us at each destination.

ecotourism group photo

Our group out on a drive. Photo by Nancy Moore

We found a whopping 399 bird species, of which 383 were well seen by the group.  This included:

  • 100+ life birds for all participants (and over 360 lifers for those new to Africa!)
  • Representatives of 15 bird families endemic to Africa
    • Ostrich (1 species)
    • Guineafowl (1)
    • Hamerkop (1)
    • Turacos (2)
    • Mousebirds (3)
    • Wood-hoopoes (2)
    • Ground Hornbills (1)
    • African Barbets (4)
    • Wattle-eyes & Batises (4)
    • Helmetshrikes (2)
    • Bushshrikes (8)
    • Rockjumpers (1)
    • Crombecs and African Warblers (4)
    • Sugarbirds (1)
    • Oxpeckers (1)
    • Plus, we heard a tantalizingly distant Striped Flufftail
  • And well over 50 species endemic to southern Africa

endemic bird Cape Batis

The Cape Batis was one of many Southern Africa endemics spotted on our trip

We also had sightings of 51 mammal species (!!) in addition to tracks of several other species:

  • These included hyrax, elephant, baboons/monkeys, bushbabies, squirrels, hare, dogs, lion, civets & genets, hyena, mongoose, zebra, rhinoceros, warthog, hippos, giraffes, and loads of antelope & relatives – several of which were endemics

Highlights – there were so many that’s it hard to list just a few!  On the return flights, Heidi & Jay discussed trying to list their favorite (“top ten”) bird species as well as best moments of the trip.  At the risk of leaving out many species and experiences, here’s an attempt at a list:

  • Favorite birds:
    • Double-banded Sandgrouse – they made us wait before giving great views at a watering hole and then in the Mopane woodland.


      Sandgrouse are not, in fact grouse, but their own unique group of birds!

    • Common Buttonquail – great, close looks at a pair.
    • Collared Pratincole – so many great views, during the day and many hundreds at dusk.

      collared pratincole adult and juvenile

      We had excellent views of Collared Pratincoles throughout the trip. This unusual shorebird is much like North America’s Common Nighthawk in both behavior and morphology

    • Red-throated Wryneck – a great view for half the group in Johannesburg then a cooperative bird for all at Dullstroom.
    • Terek Sandpiper – long on Jay’s wishlist, we saw an early arrival at Langebaan lagoon.
    • Bronze-winged Courser – close looks at this unique “shorebird” in burnt woodland.
    • Verreaux’s Eagle – what a great looking eagle … and at a nest!
    • Cape Rockjumper – great color patterns on a cooperative pair.
    • Taita Falcon – sad to see a solo male of this rare species but a neat sighting (& we just got word through Alastair that a female has been sighted at this famous nesting spot for the first time since the prior female disappeared several years ago!)
    • Black Harrier – a stunningly unique (& endemic) harrier.

black harrier

Although Harriers are a common group of raptors around the world, the Black Harrier (Circus maurus) is a unique example of its genus

  • Favorite moments:
    • Wild dogs (!) in Kruger, including pups
    • Flight to Gorongosa from Beira to see the surrounding landscape
    • Roaring lions at dusk
    • Bathing adult and juvenile male elephants
    • Howling hyena (very close to us)
    • 24+ species “bird party” with Stierling’s Wren-warbler in Gorongosa that had Alastair & Test (lead guide in Gorongosa) giddy

      wild dog in Kruger National Park

      Denning Wild Dogs with pups were a highlight in Kruger National Park

    • Great Bittern – a lifer for Alastair on our first morning with him
    • Mousebirds racing alongside our van for ~500 yards @ over 35km/hour
    • Pelagic feeding frenzy with 3 species of albatross plus petrels and shearwaters
    • A distant meerkat south of Johannesburg (Suikerbosrand)


Hyenas are an important meso-carnivore in most African ecosystems. Hopefully sights like this (from our visit to Kruger National Park) will soon be common in Gorongosa

We highly recommend considering Mozambique and South Africa for a future birding trip – you’ll be wowed by all the mammals and the birds will blow your mind :-) . And, after how well this pilot trip went, this won’t be our last trip to Africa! Let Jay know if you’d be interested.

Read more about our trip from Alastair’s perspective in this Mammoth Safaris blog post: “Gorongosa Revisited“.

male lion in Gorongosa National Park

One of “The Senators” of Gorongosa. These battle-scarred male lions were given this name because they were discovered during the week when Idaho’s Senators were visiting the park!

Gorongosa Research Update

IBO continued its work in Mozambique at Gorongosa National Park in 2017. We are now tracking both African White-backed and White-headed Vultures using satellite telemetry (Check out this map on our web site). A team visited the park in June and successfully deployed 6 transmitters on White-headed vultures. This species is one of Africa’s most endangered vultures.  

Gorongosa likely contains the densest concentration of White-headed Vultures anywhere in the world!

Tracking the birds will help us understand vulture movements and identify threats to their populations. These studies by IBO are part of a continent-wide effort to better understand vulture movements and further their conservation.  

Teague Scott and Eric Hallingstad with White-headed Vulture

Teague Scott and Eric Hallingstad attach a wing tag to a White-headed Vulture

Western Ecosystems Technologies, Inc. (West) was a key part of our 2017 efforts. They provided the satellite tracking units and helped us attach the transmitters. West employee, Eric Hallingstad, has been instrumental in ensuring continuation of this project.

Greg Kaltenecker and Andre Botha with White-headed Vulture

Greg Kaltenecker and Andre Botha with a White-headed Vulture

New partner, André Botha, a South African biologist with The Endangered Wildlife Trust, was also a critical member of the 2017 team. He worked with us to capture raptors and deploy transmitters and wing tags. Andre has been a leader in development of the newly completed African-Eurasian Vulture Multi-species Action Plan. We’re excited to see new partnerships like these develop as the Gorongosa project grows!

Teague Scott attaches a transmitter to a White-headed Vulture

Teague Scott attaches a transmitter to a White-headed Vulture

Five-year Lucky Peak veteran, Teague Scott, started his MS in Raptor Biology at Boise State University this summer. His project is focused on the critically endangered vultures of Gorongosa. Teague will analyze satellite tracking data, compare movements of the different species, and describe nesting activity within the park.  

Amemarlita and Diolinda with Bateleur

Research Fellow, Amemarlita de Matos, and Gorongosa Intern, Diolinda Mundoza Semente, band and measure an immature Bateleur

For a third year, IBO mentored and hosted a Mozambican intern to our Lucky Peak research site. Amemarlita de Matos has a strong interest in birds and science and was a fantastic Lucky Peak intern this fall. She is assisting IBO in Gorongosa with the vulture research as well as road-based raptor surveys designed by our own Robert Miller. Ame’ has also conducted a study of nesting Pink-backed Pelicans at Gorongosa.

We are looking forward to continuing our research at Gorongosa over the next three years, with support from the Greg Carr Foundation, McDanel Land Foundation, Western Ecosystems Technologies, Inc., Boise State, and others. The annual meeting of the Raptor Research Foundation will occur next November in Kruger National Park, South Africa. We plan to have a strong showing at this conference, presenting data on vulture movements and nesting behavior, results from raptor surveys, and more!  

Thanks to all IBO staff, funders, Gorongosa park staff, and dozens of others who have made this important work possible!

Hummingbirds and Climate Change: What can pollen tell us?

For years IBO has dreamed of adding pollen sampling to our summer hummingbird monitoring project to help us learn more about hummingbird diet. Thanks to some funding provided by the Murdock Partners in Science Program we have finally been able to make that a reality!

Sexy Calliope Hummingbird

The diet of Calliope Hummingbirds isn’t well understood. Photo by Heather Hayes

The Partners in Science Program

In 2017 we started an exciting new project as part of the Partners in Science Program. This program pairs high school teachers with researchers at universities to provide two summers of research experience for science teachers. We’ve had three successful Murdock teachers work on songbird banding projects in the past–Larry Barnes, Lindsey Lockwood, and Steve DeMers — but 2017 marks our very first hummingbird Murdock project.

We lucked out and found a great teacher to take this project on. Kate Dircksen from Capital High School is a science teacher with a background in Botany. This made her the perfect candidate for this project since she knows a lot more about Idaho’s wildflowers than we ornithologists do!

Hummers and Climate Change: Why does this matter?

Hummingbirds evolved to use day-length cues to decide when to migrate. In the past, day-length was matched with plant flowering and hummingbirds nested during peak blooms. Climate change is causing a breakdown in this connection; flowers are appearing earlier because of earlier springs. But hummingbirds follow the same day-length every year and may arrive too late to catch peak flowering.

Pollen samples from hummingbird foreheads will help us learn what plants hummingbirds use and when. We want to document their favorite plants and understand how climate change affects these. This will be important for planning the best way to conserve hummingbirds in the future.

sampling hummingbird pollen

We collect pollen from hummingbirds using a syringe filled with a gelatin mixture

Discoveries this summer

For our first summer we focused on building a pollen library from plants at our hummingbird research site in Idaho City. Kate collected and made microscope slides of more than 90 pollen specimens. We catalogued pollen grains from more than 70 different species of wildflowers in the Boise National Forest.

pollen grains from fireweed flowers

Fuchsine stain helps us identify the key features of different species. Fireweed pollen from Idaho City

At the end of this summer we collected 6 test samples of pollen from hummingbird foreheads in Idaho City, and compared these samples to our pollen library. By using a microscope to view the samples we were able to discover species richness and diversity for each sample.

Summer 2018

Next summer we’ll focus on collecting more samples from hummingbird foreheads. Kate will use the pollen library to identify the pollen and determine what plants make up the diet of Idaho City hummingbirds.

Follow this link to find out how YOU could be a driving force in hummingbird conservation! 

pollen grain microscope slide

Mixed Paintbrush (Castilleja sp.) and other pollen grains from a Black-chinned Hummingbird

Curlews in the Classroom: Bringing Conservation and Kids Together

450 Wilson Elementary students settle in for a "Curlews in the Classroom" presentation

450 Wilson Elementary students settle in for a “Curlews in the Classroom” presentation

The IBO’s popular “Curlews in The Classroom” had an amazing 2017 season! IBO Outreach Coordinator, Heather Hayes, reached more than 5,400 students throughout the Treasure Valley. Through this program, 28 schools and more than 180 classes learned about the biology, life history, and threats facing North America’s largest shorebird, the Long-billed Curlew (Numenius americanus).

curlew thank you note drawing

Our unique Curlews in the Classroom presentation gives students the opportunity to meet “real life” IBO biologists, and brings first-hand knowledge and engaging stories from the field into the classroom. Students also learn about satellite tracking technology used to track curlew migration back to Idaho during March and April. Students can follow the birds on this interactive map throughout the school year.

After the initial program, teachers in the program build upon what the students have learned with some of IBO’s activities, games and STEM lesson plans (math, geography, writing, ecology, physics) that incorporate curlews.

Did you know that each Long-billed curlew that receives a satellite transmitter needs a name? Every season we like to have some fun with the students and partners that are a part of the programming and hold a Curlew naming contest! All submissions are posted on the IBO’s Facebook page and put to a public vote. Some pretty creative names were submitted this year but a few stood out above the rest.

student art curlew poster

Students from Village Charter School created signs to spread the word about curlew conservation

We would like to congratulate Middleton Middle School for naming two of our curlews “Athena” and “Zeus” from the Orchard Combat Training Center. The Boise Watershed Environmental Education Center also joined in on the fun and chose the name “Curly Fry” for one of the curlews who nests on the City of Boise’s 20 Mile South Farm. Thank you to all that participated and don’t forget to start thinking of creative names for 2018!

Curlews need YOUR help! Follow this link to aid in curlew conservation research!

Transmittered Curlew in flight

IBO Receives Grant for Short-eared Owl Survey Expansion

The Short-eared Owl has experienced a long-term, range-wide, substantial decline in North America. It is believed that the population has declined by up to 60% in the past 50 years. The species is considered “climate endangered” by the National Audubon Society Climate Project and is considered a Species of Greatest Conservation Need (SGCN) in Idaho and many other western states. However, specific information as to the cause and magnitude of the decline is unknown. Traditional survey methods such as the Breeding Bird Surveys and Christmas Bird Counts are not sufficient to address the conservation needs of this species.

Be sure to listen to Boise State Public Radio’s story on this project here.Short-eared Owl photo by KS Lopez

For the past three years IBO staff has provided in-kind support to develop and lead a west-wide survey of Short-eared Owls known as WAFLS – Western Asio flammeus Landscape Study. The program began in 2015 as a partnership between IBO and the Idaho Bird Conservation Partnership. Our goal was to specifically support the Idaho State Wildlife Action Plan.

The program engages citizen-science volunteers from across
the state in a statistically-rigorous survey for Short-eared Owls during the owl’s spring courtship period.

Pronghorn by Jim DeWitt

WAFLS volunteers get to see more than just owls! Spring is a great time to see other wildlife like these Pronghorn. Photo Credit Jim DeWitt, Frozen Feather Images

Our early success was due in large part to our generous volunteers! These results influenced the Idaho State Wildlife Action Plan and we published an article in Avian Conservation and Ecology (Miller et al. 2016). In 2016, the program expanded into Utah through a partnership with Hawkwatch International. And this year, the program expanded further into Nevada and Wyoming through partnerships with Nevada Department of Wildlife and the Teton Raptor Center.

330 participants contributed over 3,400 hours to complete surveys
across the four states in 2017. Over 80% of the contribution came from citizen-science volunteers.

Brett Bunkall survey view in Utah

Our WAFLS surveys take volunteers to some pretty fantastic views! Photo by Utah citizen-scientist Brett Bunkall

In partnership with the Western Association of Fish and Wildlife Agencies, the Pacific Flyway Council, and additional state partners, IBO applied for a Competitive-State Wildlife Grant (C-SWG) from the U.S. Fish and Wildlife Service.

We recently received word that we were awarded the grant!
This will fund the WAFLS program expansion to all eight western states for the next three years (adding California, Montana, Oregon, and Washington).

The grant will fund work to expand and operate the program for the years 2018 – 2020. IBO will continue to provide leadership for the overall program. This will include survey design, implementation, data collection and management, analysis and reporting. In addition, IBO will continue to coordinate the volunteer effort within Idaho.

Short-eared Owl by Jim DeWitt

Volunteers spotted this Short-eared Owl during an Idaho survey. Photo Credit Jim DeWitt, Frozen Feather Images

The result of our work will continue to inform State Wildlife Action Plans by providing habitat-specific trend information, addressing key research questions (e.g., owl friendly grazing practices), prioritizing specific conservation measures, and continuing our general advocacy for the species. We expect to continue to publish scientific advancements in peer-reviewed scientific journals. We will also continue our engagement with the world-wide owl research and conservation community.

If you live in one of the eight survey states and would like to become involved, let us know!

You can email for more information. Surveys require just two evenings of your time in the March – May time frame (timing dependent upon survey elevation). We will provide you with training, materials, and instructions. No experience is necessary!

Check out the Boise State Press Release about this project here.

Bioacoustics: Recording Nocturnal Flight Calls at MPG Ranch, Montana

Did you know that birds use high frequency calls to find each other at night?! This is one theory explaining why many bird species emit short (40 -150 ms), mid- to high frequency (3-10 kHz) vocalizations called Nocturnal Flight Calls (NFCs) during migration. Recording NFCs, especially in the eastern US, has become a viable method to monitor migrating birds.  

Nighttime-flying songbirds are hard to count during migration.
This project will help us monitor their movements!

More data, especially isolated NFCs from western species, will improve automated classifications of recordings in the field of bioacoustics. This Fall, the Intermountain Bird Observatory, in collaboration with and funded by the MPG Ranch in Florence Montana, piloted a research project recording NFCs in a Portable Recording Station (PRS). Think of a dark, sound-proof recording studio for birds!

Portable Recording Station with Grosbeak

Portable Recording Station with Black-headed Grosbeak just before release- Photo by Debbie Leick

IBO Research Biologist, Christian Meny, worked with University of Montana Bird Ecology Lab’s (UMBEL) bird banders on a floodplain site at MPG Ranch to run the PRS. After banding, birds were placed in the PRS- an acoustically isolated recording booth operated in a dark hunting blind in order to simulate night.  

Our recordings will help calibrate computers so they
can count and identify flight calls of birds passing overhead

Birds in the PRS experience a minute of complete silence, followed by two minutes of stimulus playback (recordings of NFCs given by conspecifics or closely-related species), and then another minute of silence. Birds sampled include warblers, sparrows and thrushes because of their families’ known proclivity for emitting NFCs during migration.

Spectrogram of an Orange-crowned Warbler call note

Orange-crowned warbler nocturnal flight call recorded in portable recording station at MPG Ranch- Photo from Raven Pro 1.5

Overall, we recorded a total of 84 NFCs! Highlights include true NFCs “elicited” from Orange-crowned Warblers, Gambel’s White- crowned Sparrows and from one individual Fox Sparrow. Various vocalizations were recorded from Chipping Sparrows, Common Yellowthroats, Dark eyed Juncos, MacGillivray’s warblers, Lincoln’s Sparrows, Song Sparrows and Wilson’s Warblers. These data will help classify and catalogue bioacoustics data in the Intermountain west, and contribute to other bioacoustics projects including MPG Ranch’s Project Night Flight: an effort consisting of 20 passive microphones recording the night sky (and migrating birds) across much of the Bitterroot River Valley in Montana.



Yellow-billed Cuckoo Survey Update

If you asked a room full of birders, biologists, and researchers alike this question “How many of you have seen a Yellow-billed Cuckoo in Idaho?”, probably only one or two hands would raise, and the rest of the room would roll their eyes and sigh in an expression of their desire to see one of these elusive birds. So what is the deal with cuckoos?

Tempe conducts a Yellow-billed Cuckoo survey

Tempe conducts a Yellow-billed Cuckoo survey along a targeted strip of riparian habitat

The western population of Yellow-billed Cuckoos is recognized as genetically distinct from the eastern population and has declined dramatically in size and range extent since the 1950’s. This decline is mostly due to loss of large cottonwood galleries and riparian habitat. This population was listed as threatened under the Endangered Species Act in November of 2014. Yellow-billed Cuckoos are more commonly encountered in southwestern states like California, Arizona, and New Mexico. Idaho represents the more northern extent of their range and the status of cuckoos in Idaho is not clear.

In 2017, IBO received a contract to conduct surveys for Yellow-billed Cuckoos within the Bureau of Land Management’s Shoshone Field Office. This area contains a large swath of U.S. Fish and Wildlife Service Proposed Critical Habitat, as well as other potentially suitable habitat for Yellow-billed Cuckoos. To conduct these surveys, we applied for and obtained a U.S. Fish and Wildlife Service federal permit allowing us to use playback (broadcast of cuckoo vocalizations) to survey for these rare birds. It is important to note that only people specifically permitted can use playback to detect cuckoos.

A small crew, lead by Tempe Regan, with assistance from Jay Carlisle (IBO Research Director), Jeremy Halka (IBO Research Biologist), and Idaho Fish and Game biologist Ross Winton and his technician Austin Young, were able to survey 19 sites completely, visiting them four times, each visit two weeks apart, from June 15 to August 15. Most of the surveys were in the Little and Big Wood River drainages. Overall, they surveyed a total of 197 points, four times, for a total of 788 individual survey points for cuckoos. Although they spent hours, days and months looking for cuckoos, they only detected a Yellow-billed Cuckoo on just three of 788 individual survey points and at one of 19 sites. All of the Yellow-billed Cuckoo detections occurred on the same day at the same site!

The first cuckoo!

On the first day of cuckoo surveys, Jay looked at Tempe and said “So, do you think you are going to get a cuckoo this summer?”. She laughed and replied “Yeah, one!”.

Just minutes later, on June 16, 2017, they detected a Yellow-billed Cuckoo at point five of that morning’s survey!  

They heard the bird giving the typical “kowlp” contact call after the second sequence of broadcasts had just ended. Tempe and Jay looked at each other in disbelief and mouthed “no way, did you just hear that!?” almost simultaneously. Eventually, they were able to see the bird before it flew away and estimated it was just 20 meters from them!  

After they calmed down and had collected the necessary data, they moved to the next survey point (point six), and again detected a Yellow-billed Cuckoo – first as it silently flew in from the southeast, and then when it gave the “kowlp” call from across the river. Finally, at the last point (point eight) of the site, they detected a Yellow-billed Cuckoo again giving the “kowlp” contact call, and then observed it feeding ~ 34 m away. It made for an exciting morning and believe them when they say a Yellow-billed Cuckoo hunting for caterpillars is a cute sight indeed!

However, they had no idea how right Tempe was when she predicted it would be downhill from there. Sadly, this proved to be true and they did not detect another cuckoo at this site or at any other site for the rest of the season!

The first (and only) Yellow-billed Cuckoo spotted during 2017 surveys. Photo by Austin Young

We cannot determine with certainty the actual number of cuckoos detected during the morning of June 16, as it may have been just one cuckoo following them along. Most likely, they detected a migrating cuckoo because that detection was during their first and earliest visit to the site (when cuckoos are still migrating, especially into the northernmost extents of their range – i.e., Idaho).  

Next year, we hope to continue standardized surveys for cuckoos in the BLM Shoshone Field Office and potentially expand the areas to be surveyed. We also may begin work to find funding to research other aspects of the biology of these seldom-seen, but often-sought-after birds.