An adult Yellow-rumped Warbler captures a Mayfly to feed her chicks along the shore of Swiftcurrent Lake, Glacier National Park.

Opportunities to photograph wildlife in Glacier National Park are abundant.  They are among the things I love most about Glacier.  The actual practice, however, can be problematic particularly along the roadways.  Visitors are always on the look out for big wildlife.  So anyone stopped by the side of a road who merely looks intently off into the distance is bound to attract attention.  That same person pointing a big lens at something, let's say a bear, will in minutes turn an empty road into a helter skelter 20 car "Bear Jam", with the guarantee that Park Rangers will arrive shortly to break up the melee.  Bear jams, sheep jams, goat jams, they’re all fairly common.

Jams aren’t always restricted to mammals.  I was once pleasantly delayed in my travels by a grouse jam.  Perhaps most amazingly, I personally (and unintentionally) managed to create a wildflower jam as I photographed Oregon Grape by the side of the road leading to my campground.  Oregon Grape_JF01168Creeping Oregon Grape (Mahonia repens), is a very low growing, evergreen "subshrub" rarely reaching more than 10" in height. Though its leaves look like American Holly, they are distantly related.

It makes a good ground cover where it is native. Beautiful in many seasons, with yellow flowers, dusty blue fruit and older leaves that turn yellow before dropping. What people thought I was shooting, as I sat aiming my camera at the ground two feet in front of me, I don’t know.  But they backed up traffic anyway to stop and ask.  At least this was a short-lived jam.  No one joined me to gaze at the Oregon Grape.

Over the years I've tired of the chaos that can come with shooting by the side of the road.  Now I tend to seek out animals in locations where I don’t have to worry about attracting unwanted attention or creating traffic jams.  And this is partly why during my last visit I focused my photography on a less appreciated group of Glacier’s wildlife: birds.  And I was richly rewarded. ¹ 

I selected an area along the shore of Swiftcurrent Lake where I noticed a fair amount of bird traffic during a previous visit.  Pushing aside some branches, I found a narrow but well-worn foot path I hoped would lead me to the sliver of shoreline I had noticed earlier.  Ahead, but well out of view, was the mouth of Swiftcurrent Creek where it opened into the lake.  The broad delta it formed was a tangle of willows and alders.  A flycatcher sang atop one of the willows.

I hadn’t gone far before the path disappeared into the tangle. Though I tried to find its continuation the vegetation was too dense.  Twigs scraped against my face, camera and lens, ultimately convincing me to return to where I lost the path.  Working my way closer to the lake I found a depression only narrowly separated from the lake by a small rise of rich organic humus topped off with bunches of grasses that kept the soil from being washed into the lake.  The bottom of the depression was black organic muck.  Moose tracks were impressed in the muck.  Seems I wasn’t the only one interested in an easier route.  

Where the depression ended I was left with the rocky shore leading away with a gradual leftward curve.  I settle down on the last clump of grass, getting as low to the ground as possible without sitting in the water, set up my tripod and covered myself, my tripod and camera in a camouflage mesh.  

My movements along the shore, and especially that last act of donning camouflage, all came with a fair amount of reflection on the fact that I was in grizzly country, had just stepped into fresh moose tracks, and visibility in the direction of land was limited to not much past my nose.  The good news?  The brush was so thick I was bound to hear anything approaching by land.  Still, I patted the left pocket of my vest; the pepper spray was still there. 

Ahead of me lapping waves, so gentle one might hesitate to call them waves, had washed away the soil of the delta revealing just how thin it really was.  Where the reach of the waves ended soil and vegetation abruptly began.  Shrubs clung to the soil, their branches stretched out toward the lake to claim the only open sky available and in the process created patches of sheltering limbs and shade from which land-loving birds that ventured onto the shore could find some sense of safety in this exposed environment. 

Northern Waterthrush (Parkesia noveboracensis)Fresh Catch! An adult Northern Waterthrush moving like a pro along the rocky shore, quickly spied and snatched this newly hatched mayfly (termed a "subimago") . Note the mayfly's exoskeleton directly below the mayfly.

Once settled down with my longest lens, it wasn’t long before I seemed nearly invisible to the many avian visitors to the shore.  The narrow, curving sliver of shoreline acted like a runway, with birds entering from the brush at the far end and gradually making their way toward me as they hunted their prey.

Glacier in summer is alive with birds of every kind busily raising their young.  Most of the species I encountered along the shoreline were warblers (Yellow-rumped, McGilvary’s, Common Yellowthroat and Northern Water Thrush) and sparrows (Chipping, White-crowned, Song and Lincoln's).  Some of these species are not normally considered shoreline inhabitants.  But the reason for everyone's presence soon became apparent - the mayfly hatch.  

Mayflies spend the early stages of their lives in the waters of healthy lakes, streams and marshes.  "Healthy" being the key.  Mayflies are often used in the scientific evaluation of streams as an indicator of health, as they are unable to live where nutrients are excessive or where too much sediment has entered the water, coating what would normally be a clean, rocky bottom.  

Cedar WaxwingEven the Cedar Waxwings, that normally feast on fruit will take advantage of mayfly abundance.

Most of the mayfly’s aquatic life is spent in an immature flightless form called a “nymph”.  Nymphs feed on the microscopic algae and detritus of aquatic beds.  By mid-summer nymphs are ready to emerge from their watery world.  Rising to the surface, the nymphs of Swiftcurrent Lake climb barely above the waterline onto dry land before escaping from their old exoskeletons to become winged creatures.  Once they have emerged their lives are short.  In a matter of a few days they will  fly for the first time, molt once more, form swarms to mate, spread their eggs over the same waters from which they had just emerged, and die.  During this time they will not eat.

Mayflies of various species are common across North America.  In some parts of the U.S. the mayfly hatch is so huge it shows up on weather radar.²   Billions of mayflies in a synchronized hatch swarm in the air and after mating land everywhere as they die.  The numbers are so high that predators can’t put a dent in the supply.  Mayfly carcasses pile up on roads, cars, sidewalks... and must be shoveled away.  

The hatch I witnessed in Swiftcurrent Lake was much more subdued.  Surveys in Glacier have documented a total of 21 species of mayflies park-wide.³  In Swiftcurrent Lake at most 7 species have been documented.  Those I observed seemed to emerge more gradually, and definitely in fewer numbers.  

Still, their presence is important.  As the nymphs crawl onto dry land to transform into winged mayflies they are temporarily immobile and vulnerable, making them a ready source of food.  And how providential that this happens right when bird parents need to feed hungry chicks.  

During the few days I visited this shoreline in early August, I found many avian young already out of their nests, following their parents and begging for food from the relative safety of the shore's brushy edge.  Every parent on every trip found at least one mayfly to bring them.  Often several were stuffed in their bills before flying back to their chicks.

Other fledglings, juveniles already independent of their parents, wandered the shoreline and thickets in search of prey.  I learned to spot them by their hesitant movements and the unique disarray of their feathers: the remnants of their nestling down still poking out from their incoming flight feathers.  I was sure I was photographing some of these young literally making their first attempts at finding their own food, hopping  Juvenile Common YellowthroatVenturing onto the shoreline for perhaps the first time to find food. Even his posture suggests he is still used to begging food from his parents. in their awkward way around the rocky shore and, despite their inexperience, easily catching a helpless mayfly packed with fat and protein.  

Yes, it was easy for them to find food.  Very easy.  It was like watching a 2 year old on his first Easter egg hunt, bumbling up a grassy knoll, finding all those brightly colored eggs "hidden" in plain sight by a loving parent.

And through stillness, patience, watching, and learning I found my reward in the hunt - kinship with these young birds along this sliver of rocky shoreline, as they and I discovered more about this World of God's making.  I was reminded of what Luke tells us, that Jesus would often steel away to lonely places to pray.  I wondered if he may have spent some of his time considering the birds of the air.  A prelude to him teaching his disciples about the simplicity of trusting a good God for the needs of the day and thereby gaining freedom from worry.

Consider the birds of the air “... they neither sow nor reap nor gather into barns, and yet your heavenly Father feeds them.  Are you not of more value than they?  ...But seek first the kingdom of God and his righteousness, and all these things will be added to you.”  ⁴

All photos and text are Copyright © Julia Flanagan unless otherwise noted.  All rights reserved.
 

References:

1.     A good way to learn more about birds on your next visit to a national park is to take a tour led by a Park Ranger.  Many parks will have tours specifically related to birds.  In Glacier I took an excellent birding tour led by Park Ranger, David Benson.  It was a leisurely stroll from Many Glacier Hotel around the edge of Swiftcurrent Lake, through Many Glacier Campground and out onto the trail to Swiftcurrent Pass that introduced me to a variety of habitats and locations that were excellent for birding.  It was a great introduction that encouraged me to explore these and more areas with my camera and expand my understanding of the birds of Glacier.

David is the author of the field guide “Glacier Is For The Birds“.  Available here  https://shop.glacier.org/glacier-is-for-the-birds     

2.     Weather Radar captures billions of mayflies hatching on Lake Erie. 

 https://www.freep.com/story/news/local/michigan/2019/07/05/mayflies-lake-erie-weather-radar/1658606001/

3.     Newell, R., & Baumann, R. (2013). Studies on Distribution and Diversity of Nearshore Ephemeroptera and Plecoptera in Selected Lakes of Glacier National Park, Montana. Western North American Naturalist, 73(2), 230-236.

4.      Matthew 6:26, New International Version, 1984.