Friday, August 23, 2024

Boreal Owls Breed in Utah's Uinta Mountains

Juvenile Boreal Owl Siblings Observed in the Uinta Mountains
Wasatch County, Utah July 2024

Let the Juvenile Boreal Owl Search Begin

Where do Boreal Owls breed in Utah's Uinta Mountains? How widely are they breeding? These and similar questions have puzzled and challenged Terry Reid, James Loveless, and me for several years. We've searched online to find information about the species in Utah, but it seems that very little research has been published with regard to the Utah populations of Boreal Owls. Most of the research we find online has been done to study populations in our neighboring states of Colorado, Wyoming, and Idaho. BirdsOfTheWorld.org includes a statement under the Breeding Range section for the species that "although there are no confirmed records, breeding is probable in the mountains of Utah." We have a friend who is an ornithologist who observed a nest over twenty years ago. We also know that our work over the past few years inspired a college student to conduct breeding bird research during this year's breeding season. We are eagerly awaiting his results.

Since we individually had our first Boreal Owl encounters in the Uinta Mountains (the Uintas) in late August and September of 2020, we have made repeated individual and joint trips to remote and rugged areas to learn as much as possible about the natural history of the species in the field.  My friends and I are hobbyists, not ornithologists, but we've deliberately endeavored to contribute to science by adding data to the heretofore-thin body of knowledge for the species in Utah since 2020. We united our efforts in the fall of 2022 to execute a plan to document the wide-spread presence of the species by locating, photographing, and recording vocalizations of them in five distinct locations throughout the western end of the Uintas. The surprising results of those efforts were shared in a previous post at this link. Our discoveries, once made public by our eBird reports and NeoVista Birding and Wildlife blog posts, ignited interest in and attention on the species. Members of the local birding community as well as out-of-state visitors have "flocked" to where we made our original discoveries.

This post shares some of the results of a personal project we completed this summer to document as many juvenile Boreal Owls as possible in the western portion of the Uinta Mountains. The objectives were to document evidence that Boreal Owls breed in the Uinta Mountains and capture images of hatch-year birds at various stages of molt to help prove a theory that we have that many of the adult-looking birds that have been observed in small groups during previous fall months are actually hatch-year siblings that have molted into adult-like plumage and are still associating with one another. Based on our results for the western portion of the Uinta Mountains, we believe that the species is present and breeding throughout the Uinta Mountain range at the right elevations and in their preferred habitat. We would love to help biologists from the state of Utah study this species should that opportunity become available.

Our Approach to Gathering Breeding Data

The winter snowpack in the Uinta Mountains can reach as high as ten feet in some locations. Consequently, Mirror Lake Highway, the main access route to the western portion of the Uintas where my friends and I have focused our efforts, is closed from the first major snowstorm until typically sometime in late June. These circumstances make it logistically challenging to access high-elevation Boreal Owl breeding habitat during courtship, when male Boreal Owls are actively singing to draw mates to potential nest sites. Snowmobiles can be used to access breeding habitat via the main highway during winter, but they come with a level of risk in harsh and remote conditions. Rather than make the efforts to use snowmobiles to find males singing for mates at potential nest sites in February and March, my friends and I decided to look for and document recently-fledged juveniles during the summer months when we would have the ability to cover more breeding habitat safely in a shorter timeframe using our trucks.

When we began to figure out how to find Boreal Owls in the Uintas in the fall of 2020, we noticed that it was typical for us to locate multiple birds at a time. We theorized that those birds were members of family groups that were still interacting with siblings and possibly parents. It seemed reasonable to believe that hatch-year birds could have molted from their distinct juvenile plumages to adult-like plumage in the five to six months between hatching around mid-April and our annual observations of them in September and October. Our theory seemed worthy of testing when we studied molts for the species on the Birdsoftheworld.org website. In order to have evidence that the birds hatched in the Uintas and molted to adult-like plumage over a specific time period, my friends and I would need to get photos and audio recordings of them while they were showing juvenile, transitional, and adult-like plumages. The window for doing that would be from the time the roads open in late June through July and mid-August, before the hatch-year birds would start looking and vocalizing like adults.

We had half-heartedly tried finding juveniles a few times over several summers without success, so we puzzled over where they would nest and how far they would wander from nest sites over what period of time. Would nests be in mature aspen stands, old spruce-fir stands, or both? At what elevation? How could they possibly feed and raise families at elevations where the snowpack could be six, seven or ten feet deep? The questions were endless, but so was the determination to find answers. Consequently, we plotted several target areas and began an earnest search on July 11, 2024

Our Initial Juvenile Boreal Owl Discoveries

Fortune, planning, and determination combined the evening of July 11, 2024 when a juvenile-finding streak began for us. And, just to be clear, we chose different locations each time we went out to locate and document the presence of juveniles. We did not want to encounter the same birds on subsequent trips during the season. Thus, our impact on the individual birds would be minimized.

We decided to begin our summer search in a spot that I had checked unsuccessfully three years earlier.  I was playing a Boreal Owl recording from my phone when I heard the faint begging call of a juvenile Boreal Owl. It was the first time hearing the begging call from a live bird, so I felt a rush of excitement. I alerted my friends to tune in to the sound. We faced the direction of the begging bird with our hands cupped behind our ears as if we were parabolic receivers. There was no wind at that time, so we were able to hear a sound that rose ever so slightly above the silence surrounding us. Wow! The excitement! And then there were two birds broadcasting their begging calls in response to my playback. We followed the call of one bird deeper into the forest and got our first visual observation of a juvenile Boreal Owl in the Uinta Mountains. The bird didn't sit still for long, but we managed to capture some images along with recordings of the begging calls to document the encounter. The perceived look of curiosity in the eyes of that bird left an indelible image in my mind's eye. It was already showing some plumage traits of an adult bird. White feathers were beginning to overtake the chocolate-colored face of a juvenile and the sooty underside was giving way to the light and dark spotting and streaking of an adult. I could imagine at that time how continued molting over the next six to eight weeks would have that bird looking more like an adult than a juvenile. In other words, it would look like the numerous birds we had observed in September and October in previous years. It's not a high-quality image, but the following image memorializes our first observation of a juvenile Boreal Owl in the Uinta Mountains.

Juvenile Boreal Owl observed in the Uinta Mountains, Wasatch County, Utah July 2024

And here is a recording of that bird as we initially heard it begging. It may help to ensure that your volume is up when listening to the audio files. There may be a slight delay after clicking play because the play button is a link to audio files that are stored in a separate Google Drive folder.



We were elated by the success that we had just experienced and would have called the night wildly successful before we drove to and tried our second location for the night. Within moments, we heard one, two, three, then four juveniles begging. An adult showed itself at that location as well. We suspect that both parents were present, but we never saw more than one adult at a time. We ended the night with a total six juveniles and at least one adult from two distinct family groups. As it turned out, we were just starting what would be an unfathomably successful summer of discovering and documenting juvenile Boreal Owls in Utah's Uinta Mountains. Where only a few poor phone video or digital images may have existed in the public space for juvenile Boreal Owls observed in Utah, we would soon add numerous high-quality images, video, and audio recordings of them to public data, primarily through eBird and NeoVista Birding and Wildlife blog posts. It was exciting to be making Boreal Owl history in Utah. Below are images of two juveniles and one of the adults from our second family group.

Juvenile Boreal Owl, Wasatch County, Utah July 2024

Juvenile Boreal Owl, Wasatch County, Utah July 2024

Boreal Owl Parent Found With Four Juveniles, Wasatch County, Utah, July 2024

At one point during our observation of the second group of juveniles we heard an adult respond to the begging call of one of the juveniles. That interaction is captured in the following audio clip.

The following is a soft alarm, whistle, or contact call from an adult.



Here are some phone captures from a subsequent daytime visit to the locations where we located our first two family groups. Elevations were above 9500'

    

Our Third Family Group (July 17, 2024)

We made our way to a different location of the Uintas six days after our first juvenile encounter. We planned this trip using the knowledge we gained from our previous encounter. Our target area was still in Wasatch County, but it was miles from the previous week's encounter. Remarkably, we located a group of five juveniles shortly after sunset. We were able to observe two birds on a single branch while hearing three others beg from distinct locations. 

Juvenile Boreal Owl in the Uinta Mountains, Wasatch County, Utah July 2024

Juvenile Boreal Owl in the Uinta Mountains, Wasatch County, Utah July 2024

Juvenile Boreal Owl Siblings Observed in the Uinta Mountains of Utah
Wasatch County, Utah July 2024

Three separate juveniles can be heard begging in the following audio file.

We never saw nor heard an adult while observing this group, but we suspect that they were nearby.

Our Fourth Group of Juveniles (July 18, 2024)

We found our fourth group of juvenile Boreal Owls of the season the next evening when we targeted a location in Duchesne (doo-shayn) County. This encounter confirmed three juveniles and one adult. We observed two of the juveniles while hearing at least one other bird begging nearby. The adult and one of the juveniles cooperated fairly well for a few photos.

Boreal Owl Parent Observed With Three Juveniles in Duchesne County, Utah July 2024

One of Three Juvenile Boreal Owls Observed in Duchesne County, Utah July 2024

The Fifth Group of Juveniles (August 1, 2024)

I made an impromptu solo trip to a Summit County location the evening of August 1st to see if I could confirm the presence of juvenile Boreal Owls for our third county of the season. I know that county lines are human constructs that matter not to birds, but the purpose was to help show that breeding Boreal Owls were widespread, not just in isolated pockets. I had to work a little harder that evening. A new route that I tried to use to get to my target location resulted in a dead end and a single juvenile Northern Saw-whet Owl. I backtracked from that route and made my way using a more familiar route to the target location. I arrived at the general location after 11 PM under a moonless but clear, starlit sky. The wind was calm and the temperature was dropping from sixty to the high fifties Fahrenheit.

I had an adult respond with a single "kip" call at my first stop. I listened for the begging calls of juveniles for a little while with no success. A little farther up the mountain was a place that just felt right, so I spent some time there soliciting responses. I was surprised to have a couple of Long-eared Owls hover above and around me at an elevation of nearly 9600' in response to my Boreal Owl playback. There were at least two Long-eared Owls that entertained me for a few minutes as they responded to my playbacks. I was surprised to see the species at that elevation, so that became a new data point for Long-eared Owls in Utah. I was not able to get an accurate count because the owls were flying in and out of the forest, but I did see two at once. A moment later, as if they had no concern for what I thought would be predator owls flying in their vicinity, I heard an alarm call from an adult Boreal Owl which seemed to prompt a trio of juveniles to simultaneously start begging. The adult flew into a tree right next to me after I walked farther into the woods, but it flew just after I illuminated it and before I could photograph it. One of the three juveniles came in close and begged from the opposite side of a dead conifer that I was facing. That moment allowed me to capture the following recording of its repeated begs.

I was unable to get photos of the one juvenile that I eventually saw because it was adept at flying and never stayed at one perch long enough for me to get a photo. I didn't want to repeatedly bump it from its perches for the sake of a photo.

When I realized that it was 12:36 AM, I decide to call it quits. I had a rocky two-mile stretch and then a ninety-minute drive ahead of me with work appointments starting early in the morning. As I finished the roughest four miles of road that I've ever driven for Boreal Owls, I asked myself, "Who does this by themselves in such remote and rugged areas at 1 AM, with no cell coverage and miles from the nearest asphalt?" My Tacoma TRD Off Road did its job well that night. Below are a couple of images showing what is sometimes a typical road to traverse in order to get to elevations between 9000' and 10000' for Boreal Owl habitat in the Uinta Mountains.


One of the "Fun" Miles-long Roads to Boreal Owl Habitat in Utah's Uinta Mountains
Elevation nearly 10,000'

Our Sixth, Seventh, and Eighth Groups of Juveniles (August 5, 2024)

Once we clued into a few things with our first juvenile encounter, we were able to have success on each subsequent trip we made. That streak continued when we ventured to a new area that James had scouted successfully over a week earlier. On the evening of August 5th, we located three separate family groups. We worked a little harder than usual for the first group as we trekked through a dark meadow, riddled with trip hazards, and deeper into dense woods shrouded in darkness. We had so much fun navigating our way through the meadow and thick woods to locate the birds that we became a little disoriented when it came time to emerge from the euphoric encounter and return to the truck. We knew we'd be fine, but it's moments like that that cause some people who are unfamiliar with the Uinta wilderness to end up as news stories. Once we were back in the truck, Terry told me that I was like a coonhound on a scent to track down that group of owls. He teased that my role was to get the birds to come to us rather than have him follow me through the hazardous terrain and dense forests to find them. My response? Well, sometimes the difference between seeing and not seeing the target is in "the going after". We often have fun razzing one another. I've been told more than once that I was not doing my job after standing around in a dark wilderness in the wee hours of the night with no bird to show for it. But, truth be told, we all know that a journey into the wild with friends is a blessing on its own.

We saw at least one adult and one juvenile with that first encounter of the night. Two other juveniles were heard begging from separate locations. The plumage of the juvenile we observed had molted to an adult-like facial disc, white spotting on the forehead, some larger white spotting on the back, and dark streaking and white spotting on underside.

I was handholding the lens at 600mm when I captured the following video, so it was hard to hold the lens steady, but here is a short video of the first juvenile of the evening.


Images of one parent and a juvenile from the first group of that evening follow.

One Parent of Several Juvenile Boreal Owls in Wasatch County Utah, August 2024

One Parent of Several Juvenile Boreal Owls, Wasatch County Utah, August 2024

One of Several Juvenile Boreal Owls Found in Wasatch County, Utah in August 2024
The facial disc and underside are showing plumage traits of an adult bird.

One of Several Juvenile Boreal Owls Found in Wasatch County, Utah in August 2024
The facial disc and underside are showing plumage traits of an adult bird.

Topside View of a Juvenile Boreal Owl in Wasatch County, Utah in August 2024
This hatch-year bird was showing the facial disc and topside traits of an adult bird. Younger birds lack the white spotting on the back of this older juvenile.

Surprisingly, we had a juvenile Northern Saw-whet Owl fly into the tree next to the juvenile Boreal Owl we were observing. The Saw-whet didn't stay in that tree for long, but it perched in a nearby tree long enough to allow some images.

Juvenile Northern Saw-whet Owl in Wasatch County, Utah in August 2024

The second group we located was distant, but we could hear at least two juveniles begging. We chose not to track down another distant group on foot and drove to other locations where we eventually found our third group of the evening. We heard two begging juveniles that were not far from our location, but we focused our attention on the one closest to us. That juvenile was also starting to look more like an adult, so we began to wonder about how many months old the typical juvenile would be when it ceased using the begging call and introduced songs and other calls into its vocal repertoire. So far, none of the juveniles that we'd heard made any vocalization other than the begging call. We suspect that they will transition from begging calls to adult vocalizations between now and mid-September because that is when our searches in previous years have tuned up only adult-like birds making adult-like vocalizations.

Preening Juvenile Boreal Owl, Wasatch County, Utah August 2024
This molting hatch-year bird is showing an adult-like facial disc and some of the dark streaking and white spotting of an adult on the chest.

Juvenile Boreal Owl, Wasatch County, Utah August 2024
This molting hatch-year bird is showing an adult-like facial disc and some of the dark streaking and white spotting of an adult on the chest.

Juvenile Boreal Owl, Wasatch County, Utah August 2024
This molting hatch-year bird is showing adult plumage traits with the whitish facial disc, white spotting on the back, and dark streaking and white spotting on the chest.


Wrapping Up the 2024 Search for Juvenile Boreal Owls

We decided to wrap up our concerted effort to document juvenile Boreal Owls during the second week of August because other priorities came into play for each of us. Up to that point, we believed that we had done a pretty significant job of gathering evidence of Boreal Owl breeding in the western portion of the Uinta Mountains. However, I personally went out to new locations during the latter part of August to document the species in new locations and attempt to get photos of hatch-year birds in their latest stages of molt. When I did get those images, only hints of juvenile plumage remained in the chest of the birds.

The last planned outing was August 16th. Unfortunately, James was unable to join us, so it was up to Terry and me to make the final observations. We decided to go back to one of our original locations with hopes of finding previous birds because one objective for the night was to gather images of juveniles in more advanced stages of molt so we could eventually add them to a compilation of images showing juveniles at various stages of the molting process. We failed to locate juveniles in our first area, so we descended from that location and made our way to our backup location for the night. It turned out that the US Forest Service had conducted logging activities in that area after we made our initial discovery, so more than half the trees in the area had been cut down and placed in "slash piles" as part of a program that helps control the spread of wildfires. I decided to come up with a third plan on the fly, which proved to be fruitful and enabled us to finish our project on a high note. We were able to see and photograph two juveniles that appeared quite adult-like. We weren't sure if these were from a ninth family group or part of a group we found weeks earlier in that general area. The first bird we saw was large compared to the second one that we observed. The large one was likely a female and the smaller one a male based on knowing that Boreal Owls are sexually dimorphic in terms of size. In fact, Cornell University's AllAboutBirds website indicates that Boreal Owls have the most extreme sexual dimorphism of any North American Owl with females sometimes weighing twice as much as their male counterpart. 

Juvenile Boreal Owl, Wasatch County, Utah in August 2024
This molting hatch-year bird is looking more like an adult than a juvenile at this point.

Juvenile Boreal Owl, Wasatch County, Utah in August 2024
This molting hatch-year bird is looking more like an adult than a juvenile at this point.

Juvenile Boreal Owl, Wasatch County, Utah in August 2024
This molting hatch-year bird is looking more like an adult than a juvenile at this point.

Juvenile Boreal Owl, Wasatch County, Utah in August 2024
This molting hatch-year bird is looking more like an adult than a juvenile at this point.

The begging call of these older juveniles seemed to have shorter notes than those of the juveniles we had observed in previous weeks.



The following image was captured in a new location the evening of August 26th, several days after I initially published this blog post. I was out on a solo trip to a location that I was exploring for the first time. I was able to locate a single Boreal Owl that was in an area that was composed mostly of spruce and fir with a few aspens. I happened to photograph it while perched in one of the few aspens in the area. Like the bird in the previous image, it turned out to be a hatch-year bird that looked very much like an adult except for some tawny juvenile feathers that remained on the belly. 

Hatch-year Boreal Owl that has molted into adult-like plumage except for tawny juvenile feathers that remain in the belly of the bird. Wasatch County, Utah (August 26, 2024)

Where every previous juvenile or hatch-year bird was issuing only the begging call, this bird was vocalizing sounds that I had heard in previous fall encounters from adult females that were interacting with smaller male birds or responding to a male song that I was using to solicit responses. I judged sex by relative size during those previous encounters while two birds were vocalizing in the same tree. Boreal Owl females are significantly larger than their male counterparts. It seemed that not only were hatch-year birds looking like adults at this point of the season, but they were also starting to vocalize like them. Perhaps that was a new data point for when in their development they begin to make adult sounds, some four or five months after hatching.



I'll finish this up by stating that I was able to observe twenty-seven juvenile Boreal Owls between July 11th and August 26th. The exact count for James and Terry varied slightly since we had some observations when the three of us were not together. I know that my friends and I are not lucky enough to find that many juveniles in eight or nine family groups, so it seems safe to say that Boreal Owl breeding went pretty well in the western end of the Uinta Mountains during the 2024 breeding season.

Various Stages of Molt For Hatch-year Boreal Owls

Here are a few of my images from this summer's juvenile Boreal Owl project to show individuals at various stages of molt. These birds likely hatched in April or early May. We found them in July and August. I've arranged them as well as I can from youngest to oldest based on the molt changes I see in them. I will add more detailed notes on each bird as I study and learn more about aging hatch-year Boreal Owls.

This younger juvenile is starting to show white feathering in the facial disc, but it doesn't have any bold white feathers appearing on the rim of the facial disc. It still has a dark chest and belly and lacks white spotting on the back.

This young bird looks similar to the one above, but has more tawny feathering in the belly.

This bird appears to be a little farther along in its molt than the previous bird. It is showing more bold white spots around the rim of the facial disc and the start of spotting on the forehead. The underside is starting to form some dark streaking that starts on the upper chest and will eventually run down the belly.

This one already has some streaking running from the upper chest down toward the vent area. The facial disc is showing adult traits with the dark rim visible on the sides and bold white spots on the top corners and running from the bill outward on the bottom portion of the rim. The forehead shows white spotting.

This juvenile looked similar to the bird above, including an adult-like facial disc with some obvious streaking on the front side, but this perspective shows that it also has white spotting on the back like an adult. The back of the head is still very dark like a juvenile as it lacks the white spotting and that will show on a full adult bird.

This was one of the oldest juveniles we found during our project. It was observed on August 16, 2024. The spotted forehead, facial disc with an obvious dark rim and patches of white feathers on the top and bottom of the rim, white-spotted and dark streaked chest and belly look very similar to an adult, but it still shows some of the tawny juvenile feathers in the chest and it was still vocalizing a juvenile begging call when we observed it.

Hatch-year Boreal Owl Looking Very Adult-like in Wasatch County, Utah (August 16, 2024)
Some tawny juvenile feathers still remain in the chest and belly areas of the bird.


Hatch-year Boreal Owl that has molted into adult-like plumage except for tawny juvenile feathers that remain in the belly of the bird. Wasatch County, Utah (August 26, 2024)

Thanks for visiting my blog. I hope that you've found this post insightful and enjoyable. The hope with every post on NeoVista Birds and Wildlife is to give readers a "new view" or perspective on nature and wildlife so we can all appreciate and conserve the awe and wonders that we behold for those who will follow us.

All the best to each of you!