Monday, July 11, 2011

La Niñas Make for Poor Beds and Aggressive Fowl (5/8/11 - 5/22/11)

*This can hardly be considered a worthwhile read without first commending the U.S. Women's National Team for an extraordinary performance against Brazil yesterday afternoon-- congratulations!

As I stood on the runway of the St. Mary's airport, gazing across the icy, windswept pavement, I had the unfamiliar sensation of truly being at "the edge".  To the north where, at any minute Stan Herman would appear, wielding his spry helicopter for the last time, lay a tremendous expanse of snow-covered hills and open sky.  Not another human for at least a three day's hike.  Behind me to the south were the last trees, televisions, and toilets I would enjoy for some time.  The overcast skies held an ominous flock of Common Ravens and blew a relentless wind that cast a stinging sensation of dirt into my eyes and the sinister clanking of barbed wire fence into my ears and nothing else -- an authentic silence unlike any I had ever witnessed. 

"No point in entertaining my nerves or fantasies of abandonment," I thought.  "But, Christ, what I have gotten myself into?"

 The last load of supplies destined for Allen Creek some thirty miles away

I suppose my pessimistic thoughts at this point could be attributed to the horrendous night that I had just endured.  For reasons unknown at the time, only to be recently illuminated, I spent the better part of ten uninterrupted hours hugging a toilet or doubled-over in an intense stomach pain that can only be described as burning.  The discomfort began to arise as Jake and I enjoyed an eerily beautiful evening of boreal birding in St. Mary's.  Perhaps the most hauntingly alluring of these moments came during our trek through a forested native burial ground where we found ourselves surrounded by the piercing cries of skulking Varied Thrush.  Despite the intense poetic beauty of the circumstances, I found myself too occupied in pain to fully appreciate this rare opportunity.  All 3.8 billion years of evolutionary instinct insisted that I delay my arrival to Allen Creek for medical evaluation.  However, stubborn tendencies and a far more pleasant morning triumphed with the aid of optimistic speculation of food poisioning.

After another full day of preparing 600 lb sling loads for Stan to fly out to the field, my first helicopter ride, and life looks at Willow Ptarmigan that had been courting on a rare patch of exposed tundra behind Kevork's tent, I finally found myself on the tundra!

The Nulato Hills as seen from helicopter

Over the next several days (and nights), I found myself both agitated and fascinated by the ptarmigans' behavior.  As I began to explore the surrounding area, I quickly picked up on the universal strategy behind every male's courtship attempts -- find a piece of exposed ground and defend it with your life.  At this point in the season, a solid sheet of snow covered the entire region, spare for the scant tussock here and there.  Apparently, bush pilots and naturalists of the region attributed the extensive snow cover to the recent La Niña, given that accumulation is generally half of what it was!  These conditions put a high premium on exposed ground, which was evident in the aggressive nature of male ptarmigan displays.  This was especially apparent at night, when several male ptarmigan would gather on patches of bare ground throughout camp and display loudly for hours.  My response to their nocturnal antics quickly transitioned from a loss of sleep due to fascination to a loss a sleep due to agitation, finally culminating in complete habituation.  Unfortunately, such a transition did not exist as the smooth, flat snow beneath my tent gave way to a sloped maze of tussocks right in the spot where I was sleeping (I'm not sure my back has fully recovered even to this day).  At any rate, it appeared to returning members of our field crew that the ptarmigan were more aggressive this year, possibly due to the reduced availability of territories that coincided with the heavy snowfall.  We all wondered how this would affect the other species, especially the curlews...

 Alaskan subspecies of Willow Ptarmigan

The first week of field work was...well, exactly how everyone envisions Alaska.  Thirty mile/hr. gusts flung razor sharp hail against our faces, temperatures scarcely peaked above 20 degrees, and, most debilitating of all, several feet of snow (up to 6 feet in some places!) made walking 10+ miles on a daily basis with 30 lb of gear, even in snowshoes, a physical nightmare.  Duly compensating for the woes of fieldwork, however, was the arrival of Bristle-thighed Curlews!  Having seen a few individuals display over camp on our first morning, we set out to known territories from last year's work to begin mapping these locations throughout the study site.

Displaying Bristle-thighed Curlew

Several sites held pairs of birds that were wasting no time getting straight to business.  Males spent their time at the center of their respective territories, vocalizing, performing spectacular aerial displays, and chasing off conspecific intruders, while females slipped by unnoticed at the edges of territories, quietly yet intensely foraging away.  How astonishing that mere hours ago, these birds had just completed a non-stop, pelagic journey of 4000 km or more, only to arrive in hellish conditions where they instantly tended to their future genetic legacies without so much as a moment of leisure!  Interestingly enough, the earliest arrival dates we detected this year were a couple of weeks behind last year's (for all species), leading us to playfully speculate that the birds just may have some way of forecasting conditions on the breeding grounds...just maybe.

In addition to curlews, and just in time for point counts, several other species began showing up in the hills.  American Pipits, Lapland Longspurs, and Savannah Sparrows constituted the first 'wave' of passerines we detected, and were heard flying over camp on a regular basis.  Despite several distant looks at longspurs in flight, it would take me a full week of searching before I finally had great looks at one on the ground.  These birds are reasonably common in corn fields of the Michigan winter, but the chance to see these birds in their snazzy breeding plumage was something I anticipated more than the majority of life birds I was expecting to see.  As such, I spent a great deal of time with this first longspur and witnessed a remarkable occurrence.  Nearby, another male began singing, prompting 'my' bird to respond instantly in song.  Shortly after, he took off in flight, ascending rapidly while singing.  At his climax, he ceased beating his wings and languidly descended in lazy spirals.  Both birds continued this flight display, eventually in synchrony, followed by bouts of song-dualing on the ground.
Lapland Longspur

As I lie on my stomach, freezing and in awe from this bird's extravagant defense of his patch of exposed ground, I found myself staring at his reason for doing so -- a nest! 

A dedicated father, indeed!

The days following these photos saw a huge increase in bird activity.  Yellow-rumped Warblers and Orange-crowned Warblers were the first warblers to show up, and sparrow activity saw a huge surge with White-crowned Sparrows, Fox Sparrows, and American Tree Sparrows joining Savannah Sparrows in day-long choruses that resonated through the snow-laden hills, penetrating the roar of gushing drainages that fed Allen Creek.  Also coinciding with the beginning of snow melt were the first signs of life from the tundra itself, with Coltsfoot and British Soldier Lichen springing to life.


British Soldier Lichen

Interestingly, despite increases in activity from all other biota of the hills, curlew activity seemed to be dwindling.  More details coming in the next post!

Sunday, July 10, 2011

A Bristle-thighed What?

I suppose that this would be a suitable moment to provide a touch of background information on one's reasons for being dumped over thirty miles from the nearest group of bipedal apes for two months...then again, maybe such pleasures require no justification.  At any rate, I've met enough people (even birders!) who have never heard of Bristle-thighed Curlews and/or Bethel, Alaska (a much more forgivable travesty), prompting me to fill in a few blanks before continuing with my ramblings.

From May 7 to June 16 of this summer I had the incredible experience of living in the southwestern Nulato Hills of the Yukon Delta National Wildlife Refuge, the second largest National Wildlife Refuge in the country and one of its most remote locations still in existence.  Rather than mirroring the nearby expanses of pond-dappled coastal tundra to the west or the prodigious spruce forests of the great Andreafsky Wilderness to the east, these hills foster a unique combination of extensive drainage networks bordered by willows with large, intervening tracts of lichen-mat tundra.  Given the novel circumstances of the landscape, it should not come as a surprise that this region supports the largest breeding population of North America's rarest and most specialized shorebird -- the Bristle-thighed Curlew.  Indeed, the only other known (viable) population of these birds exists in a very similar landscape to the north on the Seward Peninsula.

Allen Creek (Field Site)

Given the scarcity of suitable breeding habitat for this species, combined with the scabrous, isolated nature of their required habitat, two major issues stand to retard proper conservation of curlews -- a lack of habitat and a lack of information concerning the biology of curlews.  Indeed, although the species was discovered in 1789 during James Cook's expeditions of Oceania, the first nest was not discovered until 1948 -- a date that is extremely late for the majority of known species.  In light of this, the Alaska Fish and Wildlife Service and Ph.D candidate, Jake Jung developed a set of goals for a three-year study of the Nulato Hills curlew population, which, roughly, are as follows:

1)  Assess the current breeding density of curlews in the Nulato Hills for comparison to previous years in order to determine the stability of the population in the face of conservation threats such as predation by introduced predators on the wintering grounds, subsistence harvesting on wintering and breeding grounds, and, of course, climate change.  The last assessment of both populations indicated that the global population hovers around 10,000 individuals, with 6,000 birds present in the Nulato Hills and 3,000 juvenile birds undergoing a three-year, flightless molt throughout Oceania.

2)  Color band as many individuals as possible.  This becomes particularly important for study of individual behavior on the breeding grounds, but also in determining the significance of population-based "clustering" throughout Oceania (very small sample sizes indicate that curlews from the Nulato Hills population tend to winter on northern islands, while those from the Seward Peninsula tend further south).  This latter point has fascinating implications for possible reproductive isolation between the two populations.  Indeed, a recent assessment of genetic variation between the two populations shows that birds can be accurately assigned to a population of origin based on six nuclear microsatellite loci (Talbot et al. 2004).

3)  Expand on the current life history data on Bristle-thighed Curlews.  Even to this date, relatively little study has been devoted to this species, making any information that we could obtain extremely valuable.  This includes everything from arrival dates and nesting phenology to habitat selection and foraging ecology.  One of the major components of field work under this topic was sampling invertebrates (curlew food) on known territories.

4)  Survey avifauna of the Nulato Hills.  Again, given the rare occurence of people in this region, data on all species is hard to come by.

I hope that serves as a semi-adequate introduction to the project.  More curious details of curlews themselves are to come in future posts, so don't fret!

Talbolt, Sandra L., Judy R. Gust, George K. Sage, Robert E. Gill, Lee T. Tibbitts, Richard B. Lanctot, and Brian J. McCaffery. "Population Differentiation of Breeding Bristle-thighed Curlews (Numenius Tahitiensis)." (2004): 1-12. Web. 10 July 2011.