Archive for May, 2022

May 22

At the Edge of an Aspen Grove

The leaves on the quaking aspens rustled in the light breeze.

Rustling sounds filled the meadow while millions of small silvery flashes came from the copse. It was just a gentle breeze that morning but enough to make the leaves flutter. A pale green then green-silver would sparkle, and waves of these flickerings would transverse back and forth, like ripples moving across a small pond. No wonder these trees are called quaking aspens. 

A group of Tree Swallows flew around the nest box chattering away as they greeted each other.

A loud commotion came from my left. Just 20 feet away, a 6-foot high post had a birdhouse. Six chattering Tree Swallows were doing acrobatics within a few feet of the box. A pair had a nest there, and perhaps these others were trying to usurp the space. The birds never touched, but they came within inches as each twisted and turned. Their long pointed wings and broad tails providing precise control. Finally, one bird settled onto the roof, chattering lightly, and the others dispersed. At that point, I suspected this was some kind of social interaction, a morning greeting.

Tree Swallow

My attention turned to the aspen grove, and the bird I had come to find. The “chebec, chebec, chebec, ….” drifted from deep in the trees. The Least Flycatcher was singing. This species is in the genus Empidonax,a group of small, drab birds, which look virtually identical and can be reliably separated only by their songs. This individual, less than six inches long, was probably sitting on a branch four or five feet off the ground, scanning for flying insects, and giving its incessant territorial chant. The remarkable thing was that he was well outside his normal breeding range.

Sound Recording of the Willow Flycatcher singing.

I first saw this species in Western Pennsylvania when I was in high school. It breeds north from the central Appalachians through Canada and west to the Rockies. A few breed in northeastern Washington, but this site at Conboy National Wildlife Refuge in south-central Washington is hundreds of miles out of its normal range.

I was curious to find this bird for I had a strange feeling of connection to it, almost like this little guy was a brother. Except for undergraduate school, I’d spent my first 60 years living in Eastern United States before moving west to Seattle. Since settling here, I’ve felt both out of place and yet extremely content. The flycatcher, also, didn’t seem to care if it was far from its regular haunts. Several dozen birders had heard his song over the last week. He was apparently here for the breeding season.

My left hand clutched the parabolic microphone pointing toward the sound, while my right hand held my binoculars in the ready position. The digital recorder was running while I searched the understory for this elusive bird. No one was allowed anywhere beyond these trails, and if I didn’t want human-made sounds in my soundtrack, I couldn’t move. My best chance to see this individual was if it flew and landed on a visible branch. 

White-breasted Nuthatch
Red-breasted Sapsucker

Other birds were also singing on this early June morning. The elaborate warbles of a house wren came from the understory to my left, and a warbling vireo’s slurry notes drifted through the quaking leaves above me. White-breasted Nuthatches, Red-breasted Sapsuckers, Western Bluebirds, and Western Wood-Pewees also made their presence known. Headsets covered my ears, giving me a stereo concert of this forest patch at the edge of the wet savanna that covered most of this Refuge.

Suddenly, I realized a second Least Flycatcher was calling off to my left, so I turned the parabolic reflector in that direction to see if the sound would become more distinct. Yes, it definitely was a second individual. Both sexes sing in this species. The first part of the female’s “chebec” is slightly lower in pitch, but the second part is virtually identical. Males, though, are not evenly dispersed through suitable habitat but rather form clumps of small territories. It is like a classical lek system where the males all compete for females on a stage rather than be spread throughout the theater. My ears weren’t discerning enough to decide if this was a pair or two separate males. 

They have an exciting display, but I was there at the wrong time of day. For a short period after sunset, the male will climb up through the branches to the top of the canopy offering warbles, whits, and chebecs as he goes. He then performs a “flight song.” He flies up from the treetops for 30 seconds, singing non-stop, and then tumbles back down, much the way a butterfly might flutter. Of course, ornithologists think it has something to do with mating, but we don’t know the actual function of this flight song. In my imagination, I can only assume that the male goes high to become visible to a distant female who might be wandering through looking for a mate. 

A flash of brown zipped behind an aspen trunk and then landed on a dead branch a few feet off the ground. The Least Flycatcher looked off to my right, gazing up and down into the small opening under the aspens. A second later, he was gone, but a surge of energy stayed with me. This bird was living life wherever he was. 

The Aspen Grove at Conboy National Wildlife Refuge.
May 22

Dawn Chorus along Stossel Creek

The marsh along Stossel Creek in Western Washington had a wonderful dawn chorus in early May.
Wetland along Stossel Creek.

Droplets bounced from bow to bow, making light ringing sounds as they fell through the Western Hemlocks and Red Cedars. Although it didn’t appear to be raining right then, the built-up water in the trees still tumbled. Water in the Red Alders gave a little different sound in this pre-dawn light, but the songs of hundreds of Pacific Chorus Frogs dominated the dark. A wide, slow-moving portion of Stossel Creek extended for a hundred feet or more in front of me. There, grasses, bushes, and small trees grew in the wetland, the perfect habitat for these tiny anurans. The males will climb a grass stem or twig, puff out their gular sack and let forth with that song. Within five minutes, a Common Yellowthroat added its “witchy witchy witch” to the dawn chorus, and shortly an American Robin began his melodious song. The area was getting lighter, dawn was happening.

The Dawn Chorus along Stossel Creek a mile or two north of the Big Pond.

It would be another five minutes after that before I heard the long, raspy whistle of a Varied Thrush. His note lasted almost a second and stayed all at the same pitch; then, he paused before giving another note at a higher pitch. He continued this pattern, long pause, long note, either higher or lower than the previous, always different than the immediately prior one. For me, this bird symbolizes the thick coniferous forests, especially at mid-elevations, of Western Washington. I wasn’t sure they would be at Marckworth Forest in May, so this was a special treat. Their tune gives me an eerie feeling, one also of mystery and intrigue. Hearing it always fills me with envy, for I wish my house were among thick, giant conifers such that this bird sang around me each spring. But I’d found one and my heart rose with delight.

It was mid-May, and many residents and early migrants had begun breeding. Other migrants would be arriving from their southern wintering grounds over the next few weeks. The Common Yellowthroat winters well south of Washington but had come back in April. A Song Sparrow and a Red-winged Blackbird gave their unique melodies to this morning ensemble. The sparrow probably stayed here all winter, while the blackbird might have wandered in western Washington before moving back to these marshes.

The forests in the Stossel Creek valley are filled with Western Hemlocks, Western Hemlocks, and Douglas firs. It is wet forest typical of the Pacific Northwest.
The forest along Stossel Creek.

Behind me, the high pitch song of a Chestnut-backed Chickadee drifted in, and the energetic trill of a Pacific Wren filled the forest with cheeriness. Unfortunately, I’m losing my ability to hear the high notes of the chickadee. Age is catching up to me. Soon I will need to seek a hearing aid to continue listening to these birds, for spring without them is unthinkable. 

A Steller’s Jay gave his rattle, and I looked down to see what my phone thought had been calling. Last year, Cornell Laboratory of Ornithology added song recognition to their Bird Identification app, Merlin. They had volunteers go through thousands and thousands of recordings, marking which songs belong to what species, and then used machine learning to teach the app. They even used a few recordings I had made. The app said that a Northern Flicker and a Sora had called, but I hadn’t caught either in this morning’s chorus. 

I’d been there almost 40 minutes when I shut down my recorder and wondered what the chorus here might be like in another few weeks when more migrants had arrived, and some of the residents might be less vocal as they concentrate on raising young. I’ll have to come back again. 

keywords: , , ,
May 22

Oh, To Be a Northern Shoveler

Northern Shovelers were actively feeding on Central Pond at Union Bay in Seattle, Washington.

Their heads were underwater; occasionally, their eyes came above the surface, but mostly they stayed down. Somehow, they were getting breaths, but I couldn’t see how. True, their nostrils are near the base of the bill, and maybe only an instant is needed. These ducks, two males and a female, were swimming fast. The body plumage said Northern Shoveler. The males had cinnamon-brown sides, white in front and behind the cinnamon patch. The heads appeared black, showing, though, as green when the light was right, and their backs dark. The female was streaked brown and light, like so many female ducks. But I hadn’t seen their bills, those large spatula-like projections. Ornithologists created the genus Spatula for these and their three close relatives in honor of that bill.

I’d come to the Union Bay Natural Area at UW’s Horticulture Center to look for them and see if I could watch them feed on this April morning. During spring in Seattle, shovelers are often on the Central and Carp ponds. Most would be paired by this time and traveling as a unit or in small feeding groups. Finally, one raised its head entirely out of the water and showed that humungous projection. I always think that bill should cause them to fall over, but its structure makes it surprisingly light, and I suspect they have strong neck muscles. 

A pair of Northern Shovelers swim in a tight circle while feeding.

They use their bill to filter out food. These birds suck water through the front of their beaks and push it out through the lamellae on the sides. They specialize in small nektonic invertebrates, which is the scientist’s way of saying swimming critters. Probably, Daphnia and many other minute things fill the water column in these shallow ponds. These shovelers swam in straight lines, occasionally doing turns, moving their heads up and down in jerky motions. A few weeks ago, pairs were swimming in tight circles. That behavior probably stirs the crustaceans and other invertebrates, seeds, and microscopic vegetation up from the bottom, making them better for filtering. We’d had strong winds in the last couple of days, and the water column was probably well mixed. 

A female Northern Shoveler opens her mouth wide to show the lamellae that allow her to filter out microscopic organisms from the water column.
The fine lamellae on the bill of this female Northern Shoveler allow her to filter out small crustaceans and other microscopic food items from the water column.
A group of Northern Shovelers swim in an oval. Each is stirring the bottom with their feet and the one following can filter any food items stirred up.
Northern Shovelers swim in a wide oval, following the one in front to catch the stirred-up water.

Once, a year ago, on Carp Pond, I watched some shovelers swim in an oval. The oval swimming, as well as the circling, are cooperative feeding techniques. It is an ingenious way of working together, everyone benefits. They can exploit the stirred-up food items by following, filtering out the good pieces. For example, we filter out noodles and vegetables from soup by pulling a spoon full along the side of the bowl and letting the liquid drain out. These ducks suck in a mouthful of soupy pond water and then use their tongue to push the water out through their built-in sieve. 

A male Northern Shoveler actively preens while a female takes an bath in the water beyond him. These are probably paired for the coming breeding season.

At the eastern end of Carp Pond, I found a shoveler pair actively preening. The female floated in the water, using her bill to pull through the body, wing, and tail feathers, occasionally taking a vigorous splashing bath. The male stood on a log, using his bill to work all its feathers. This log must be a favorite perch for ducks. A week ago, a female shoveler had her bill tucked under back feathers on one end, two Green-winged Teal were preening in the middle, and a drake shoveler was on other end. 

I find it amazing that the skin on these ducks is dry. Water doesn’t get to their skin even when swimming. The tight barbules on each feather vein act like Gore-Tex, and the weaves are so close that water droplets can’t get through. The layers of feathers and the coating they put on their feathers make the plumage waterproof. A drop of crude oil on the plumage negates all this and allows water to seep through the plumage, reaching the skin. Birds that encounter an oil spill will vigorously try to preen off the oil. The oil is toxic, but often they die of hypothermal because of the water that reaches their skin, chilling them. Just a dime-size dot of oil may spell their death.

A male Northern Shoveler actively preens while a female sleeps. Two Green-winged Teal also care for their feathers while resting on the log at Union Bay.

Birds spend a lot of time each day taking care of their feathers. Probably, these two were well fed and preparing for an afternoon nap, if not the night. Once they felt they had thoroughly cleaned and straightened their feathers, it would be time to sleep. We do something similar before bed each night.

May 22

Anuran Chorus at Stossel Creek

Pacific Tree Frogs were in full chorus, and a few American Bullfrogs added to the performance. The marsh system along Stossel Creek provides ideal habitat for these species.

The frogs were in full chorus. Swamp stretched across the valley for a hundred yards and for a half-mile along Stossel Creek. A mixture of willows and grasses grew in the wetlands, and then a pond opened downstream from this spot. The loudness and diversity of their songs made me think that hundreds were singing simultaneously. These were Pacific Tree Frogs Pseudacris regilla, and I was trying to absorb that a tiny anuran, less than 2 inches long, could make that much sound.

They also go by the name Pacific Chorus Frog and hearing this choir made me think that chorus frog might be a better name. When one male begins to sing, any nearby male will jump right in and try to outsing the other. Each puffs out its vocal sack as it puts forth the song. This was not an organized chorus with all of them singing together, but rather each male was trying to out-compete the next. If he succeeds, a female may come his way. He needs to sing louder or differently to entice her to pay attention to him. 

In the distance, I noticed the deeper and more resonating call of an American BullfrogLithobates catesbeianus. This introduced species is a severe problem in Washington. The Washington Department of Fish and Wildlife has listed it as an invasive species. Bullfrogs grow to be big. With their legs stretched out, they can be up to ten inches long and are voracious predators, eating anything they can catch. They were natives in Western Pennsylvania, and I searched for them along the shoreline of ponds near my parent’s farm. 

At fifteen minutes into my recording, a lull of ten seconds happened. Perhaps, one male needed a break to catch a snack, and all the rest followed, but I suspect it was more likely that one sensed a possible predator nearby, and they went silent. Eventually, one male frog couldn’t resist and croaked. The rest then started back up. Barred Owls are common in these lowland forests of the Pacific Northwest and will hunt these frogs. 

Tree frogs need to breed, though; these anurans sing even if it exposes them to the risk of being eaten. 

keywords: , ,