August 21, 2020
BLUETHROAT FEVER, CATCH IT!
By Kevin J. Zimmer
Birders journeying to Nome, Alaska each spring and summer come armed with justifiably high expectations and a long target list of Beringian specialties and more widespread species of the Alaskan tundra regions that they hope to see. At, or near the top of virtually every first-timer’s list, is the Bluethroat (Luscinia svecica), a dazzling little passerine of the family Muscicapidae, a group of predominantly Old World Flycatchers. Bluethroats are vaguely thrush-like congeners of the Nightingales of Eurasia, and, along with other relatives, are part of a subfamily of thrush-like Muscicapids commonly referred to as “chats.” (The familiar European Robin is another example of a “chat.”) The various described subspecies fall into three groups based on differences in male plumage: those of northern Eurasia are characterized by having a red patch in the center of the blue bib; whereas those of populations nesting in central and southern Europe have a white throat-patch, and those breeding in Turkey are solidly blue-bibbed. The “red-spotted” birds winter in southeast Asia, migrating north each spring to occupy tundra-breeding sites across northern Eurasia, including the Russian Far East. At some point in the past, ancestors of these populations crossed the Bering Land Bridge to gain a toehold on North American shores, where they successfully colonized parts of northwest Alaska, including, in particular, the Seward Peninsula.
Although the presence of Bluethroat as a breeding species in northern Alaska was known for decades before Alaska even gained statehood, it remained something of an elusive and out-of-reach “grail bird” to the relatively small numbers of adventurous birders visiting from the “Lower Forty-Eight” in the 1960s through the mid-1980s. Known breeding sites in those years were all beyond the reach of northern Alaska’s sparse system of rough gravel roads, and seeing one required either lucking into a migrant at some island outpost (e.g. the village of Gambell, located on Saint Lawrence Island), or using a bush pilot service to access true wilderness, such as the Brooks Range. Although Bluethroats are regular spring migrants through Gambell, there were very few birders venturing there prior to the late 1980s, and finding one remained a hit-or-miss proposition.
As of 1986, when I co-led my first VENT tour to Alaska with David Wolf, there were no road-accessible, Bluethroat breeding sites known to the birding community. And, as expected, we did not see one during our tour. The following year, I returned to Alaska, this time as the sole leader of one of two overlapping VENT Grand Alaska tours (the other being co-led by Kenn Kaufman and Gene Hunn). Both groups ended up in Nome at the same time, but although we constantly shared information, each group was doing its own thing. On the evening of June 10, I opted to take my group on a post-dinner drive up the Kougarok Road, to MP 24–25, to look for a pair of Gyrfalcons reported to be nesting on the cliffs above the road. We ended up seeing both adult Gyrs, and found a singing Arctic Warbler, the first arrival of that common but late-arriving breeder for the spring.
The following morning, both VENT groups were heading up the Kougarok Road, but since we had already seen the Gyrfalcons the night before, we headed out early and skipped the nest site, pushing on toward Salmon Lake. The other VENT group had not yet visited the Gyrfalcon cliff, so that was their first priority. We had no particular target, other than to enjoy whatever Nome breeding species came our way. It was a cool, overcast morning, and the breeding season was in full swing, with most of the inhabitants of the willow thickets bordering the Nome and Grand Central rivers in full song. Stops were inevitable and frequent, as we paused again and again for the likes of Gray-cheeked Thrush; Northern Waterthrush; Wilson’s Warbler; and Fox, Golden-crowned, and American Tree sparrows, all teed-up high and singing away from the tops of felt-leaf willows; and, for pairs of Harlequin Ducks and Red-breasted Mergansers hauled out on the extensive gravel bars of the rivers. Gray-cheeked Thrushes were particularly evident on that morning; their downward-spiraling songs and distinctive call notes seemed to emanate from every willow thicket, and just a couple of hours into our morning we had already tallied more than 50 seen!
Beyond MP 27, we began to climb out of the river valley, leaving the taller willow shrub community behind. Here, the stunted thickets of dwarf willow and dwarf birch were more patchily distributed across the landscape, which was cloaked in a still partially frozen tundra, dissected by countless rivulets of melt water spawned from shrinking snowfields, and peppered by scattered boulders testifying to a glacial past. It was in this matrix, somewhere near MP 31, that I slowed for a drab brown passerine teed-up in the top of a willow shrub up ahead, a few yards to the right of the road edge. I almost passed it off as another Gray-cheeked Thrush, but it looked decidedly smallish, and too compact. So I stopped. Glassing it through the dusty windshield, and with gray sky as a backdrop, I was initially perplexed. Its back was to us, and appeared entirely gray-brown, and I could just barely make out a whitish eyebrow. My mind was grasping for purchase, when the bird suddenly flicked its tail upward with a jerk, simultaneously flaring it slightly, to reveal a flash of rufous-orange at either side of the base. “It’s a Bluethroat!” I shouted, and, on cue, it swiveled its head around to check us out, revealing itself as a male, in all of its glory! Pandemonium ensued within the van, as we worked to get everyone on this unexpected prize.
Once everyone had seen the bird well, I hopped out of the van, knowing that I was going to need to document this unexpected find with photographs. Just as I was getting close enough for reasonable photos, the bird flew, but right on its heels a second bird, this one a female, came blasting out from the base of the same shrub, and she had nesting material in her bill! Investigation of the base of the shrub revealed a partially constructed cup nest! I ran back to the van, drove past the nest shrub, made a U-turn, and pulled over on the side of the road about 20–25 yards away from the willow. We piled out, trained the scope on the shrub, and waited. Within a few minutes, the pair returned to the nest site, the female—with a mouth full of nesting material—coming in low and dropping quickly out of sight, and the male, assuming his position as sentry, prominently perched atop the same branch as before. Over the next 45 minutes, we watched this ritual repeated numerous times, always with the male providing breathtaking studies in the scope.
Upon leaving, I carefully marked the spot and headed back toward town, figuring that we would cross paths with the other group en route. Sure enough, they were about six miles down the road, out of the vehicles, and gazing intently at the Gyrfalcon nest on the cliffs above. I pulled the van alongside Kenn and Gene and asked what was happening. Kenn told me that one of the adult Gyrs was on the cliff when they first pulled up, but it had flown before they could get everyone out of the vans and scopes set up. They had maintained a vigil ever since, but with no luck. Everyone looked pretty bummed. “Well, if you’re tired of waiting for the Gyr, we’ve got a bird that you might like to chase,” I offered. After letting the suspense build for a few seconds, I asked, “How would you guys like to go see a nest-building pair of Bluethroats?” Kenn’s jaw dropped, and I thought Gene’s head was going to explode. The expressions on their faces were priceless! “Are you kidding me?” said Kenn. When I assured Kenn that I was not kidding, he rounded up his crew and followed us back to the spot. We stayed long enough to witness an encore performance from the Bluethroats (a North American lifer for all), and then left Kenn, Gene, and their group there to enjoy the show. Our discovery was relayed to other tour groups that were staying in Nome, and word spread rapidly. Over the next few weeks, dozens of visiting birders got to see “our” birds, and the resulting concentration of birders visiting the spot led to the discovery of additional Bluethroat territories farther along the Kougarok Road.
Although there were specimen and sight records of Bluethroats from other parts of the Seward Peninsula dating back to the 1920s (including many 1970s records, at least one from three miles beyond the present day end of the Kougarok Road), our record represented the first confirmed record along the Nome road system, and hence, the first “chaseable” Bluethroats that birders could drive to. The following year (1988), word got out that Fish & Wildlife biologists had located a small breeding population of Bristle-thighed Curlews centered near the far end of the Kougarok Road (MP 85). The resulting “Gold Rush” of birders found that Bluethroat densities increased from beyond Salmon Lake to the end of the road. Thirty-three years later, we now know Bluethroats to be uncommon to fairly common breeders in appropriate habitat along all three main roads leading out of Nome, with some territories within 15 miles of town.
How did these stunningly beautiful little birds escape detection for so long? Bluethroats arrive in the Nome region around the third week of May and immediately set up territories. For the first two weeks, males are busy establishing their territories and advertising for mates, which they do through exuberant songs delivered either from the tops of shrubs, or during wild, skylarking aerial performances, at the conclusion of which they set their wings, fan their tail (revealing the bold pattern), and “parachute” back to earth. During this time, in which much of the tundra is still under snow and the shrubs are just beginning to leaf out, the males are relatively conspicuous. But the song period is notoriously ephemeral, and once females are on eggs, vocal activity drops off markedly. When not singing, males, like females at all times, become incredibly furtive, foraging mostly on the ground, inside and beneath the cover of dense, fully leafed-out willow/birch thickets, and seldom venturing into the open. By the third week of June, just one month after arriving, they can become genuinely difficult to find.
Prior to 1987, the number of commercial tour groups and independent birders visiting Nome was but a fraction of what it is today, and most visiting birders came later in June, after the peak song period. Also, prior to 1987 almost none of us had any idea of what Bluethroats sounded like. Two of the participants on my 1987 trip were from Austria, and after the tour they sent me a tape recording of Bluethroats they had made somewhere in Europe. There was little in those recordings to match the songs of Bluethroats at Nome, which I found puzzling. But Kenn, whose group was treated to some song bouts by the male Bluethroat after we had left the spot, later told me that the bird appeared to be incorporating some elements of other bird songs in its own repertoire. Over the years, I’ve come to know these birds as gifted mimics, weaving in imitated phrases from neighboring species with their own distinctive cricket-like calls and gargled notes to create a vocal tapestry unique to each individual male. I have heard Bluethroats imitating passerines ranging from Cliff Swallows, Northern Wheatears, and Arctic Warblers, to Gray-cheeked Thrushes, American Tree Sparrows, and Hoary Redpolls, with the occasional Wandering Tattler or Spotted Sandpiper call thrown in for good measure! They are truly remarkable little birds, and despite having never missed them on a Nome visit in the ensuing 33 years (including over 60 tours and a handful of visits on my own), my heart still catches in my throat every time I see or hear one skylarking over the tundra of the Seward Peninsula.
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