The Mysteries World of Mergansers

Blog 15

April, 2023

Can you find the merganser in this photo?

Living in a temperate rainforest along a year-round stream one would think that there would be all kinds of creatures coming and going; the air would be filled with bird-song during the spring, animals would  be coming to the creek to drink, eat and bathe, fish would be readily seen in the clear water. After all, a stream is a natural trail, a magnet for wildlife, an ecotone or edge where two different habitats meet such that critters from both are encountered. 

This has not been the case for me here.

Yes there are resident and visitor animals, but they are spread out, secretive, often most active at night. I have read that the diversity found in Pacific Northwest forests, while similar to those of a tropical rainforest, lies more in what happens underground, within the world of microorganisms: fungus, ants, termites, etc. It is a world where creatures that decompose the abundant wood thrive. I am only just beginning to appreciate this and find ways to observe this hidden, but pulsing with life, world right beneath my feet.

Not long after I moved here, in 1999, I began to keep a journal of sorts, making note of things that I observed above ground and the date. Initial entries were the obvious; deer, elk, river otters, dippers, robins arriving, the date that the first Indian plums appeared, and the spawning runs of salmon. I didn’t record my first merganser until 2012. This surprises me that it had taken so long to see one. After all, they can be quite flashy, virtually impossible to miss, especially the males. But, I have learned that they are secretive, wary of humans, and not always nearby, especially in Rocky Brook.

The Observatory

I have what I call a “JaMexican Style Composting Toilet” situated about fifteen feet from Rocky Brook. It has come to be known as “The Observatory”. As one would expect, time is spent sitting out there, especially in the mornings. I use it year-round, so it is kind of like my perch, a place to both observe and think. It acts as a“blind”, wildlife are less apt to see me when I am in there, sitting still. 

My journal indicates that I sighted my first merganser in February, 2012. The bird was seen in the pool just below the rapids, to the right of The Observatory. This is a strategic spot, anything that swims or is carried downstream needs to pass this point. The timing first suggested that this bird was watching for emergent pink salmon from the previous year’s spawning. But in looking at Fish and Game’s data, 2011 was not a good pink salmon year. However, there had been nearly sixty coho counted that fall, so I would guess that this bird was watching for emergent coho fry.

While this initial journal entry did not note what kind of merganser it was, based on subsequent sightings, this was undoubtedly a male common merganser (Mergus merganser, known as goosander in Europe). Another common name is “fish duck” because it feeds mostly on fish. Mergansers are designed for diving, with legs to the rear of the body which facilitates powerful underwater swimming (but which makes them look awkward when trying to walk on solid ground). They also have a serrated bill for holding the slippery fish until they can be swallowed whole.  

Based on my notes, I see mergansers in Rocky Brook only twice a year, in the late winter and early spring. Adult males are sometimes seen sitting in pools below a rapids, often the very same place I first observed one. I assume they are feeding on emergent fry. in reading up on their life history in other places, males typically appear first, the females one to three weeks later. I have yet to observe a female this time of year.  

After this initial late winter/spring sighting, I do not see mergansers again until early summer. This time it is a female that I observe, always with a raft of small chicks in tow. 

Both times, as soon as my presence is sensed, they are gone; the big males take to the wing and head downstream, the females usually speed up their downriver float to encourage the chicks to hurry to safety (since they have yet to fly). 

Salmon Alerts

Mergansers and eagles are the two “indicator” birds that alert me to the presence of salmon. Bald eagles tend to stay along the Hood Canal shoreline, three miles downstream.  A meal is much more dependable there. However, when there are large salmon or steelhead up the Dosewallips or in Rocky Brook, at least one or two bald eagles move upstream and perch in a tall tree, watching for their chance to swoop down and feed. They announce their presence with their fluty call, which I have come to recognize. This only happens from September through December though, the general spawning season here. Otherwise I rarely observe eagles along Rocky Brook or my stretch of the larger Dosewallips river.

Adult male common mergansers alert me in a different way. They are not much interested in the big spawning fish, rather they feed on small fry and fingerlings, and, I would guess, sometimes  eggs. I do not hear them, but seeing them tells me that salmon have emerged from their time in the gravel to become free swimming fry. This usually happens from January through March. I will walk down to the Observatory and be startled by the flash of white as an adult male merganser takes to the air and heads downstream, uncomfortable with my presence.

I was reminded recently of a third salmon alert system I depend on: Washington Fish and Wildlife biologists doing their somewhat regular stream walks. It being mid March, I was surprised to notice orange tape flagging three places right across from the Observatory. It could mean only one thing, they had walked the stream and marked redds (places where gravel had been moved around and eggs fertilized and deposited). This time of year, they had to be steelhead or rainbow trout. 

I took time to sit by the area, hoping to see some actual fish. No luck. I returned with a powerful flashlight at night and scanned the area, expecting to see some activity (steelhead seem to be more active under cover of darkness), but again, nothing. 

I could only conclude that I had missed the actual spawning, but that was okay. The redds told me that there would be steelhead or rainbow trout fry in Rocky Brook this year. Something more to look for in the coming months.

Merganser Take-Aways

Back to mergansers. So far I have learned three things about them.

1. Rocky Brook is only an occasional feeding ground for mergansers. They go up to the falls to check out the larger fish in the pool below it and floating down, past the Observatory, a trip of about a quarter mile. This happens only twice a year, first with males in the late winter early spring, then with females in early summer. 

2. The much larger Dosewallips is where mergansers must nest in cavities in trees, and reside for much of the year. It is a bigger, wilder river where it is much less likely that these wary and secretive birds would be disturbed. The Dosewallips also has more dependable feeding opportunities. 

3. I am mostly seeing the common merganser so far. As its name implies, it is the most numerous of the tree species possible. The red-breasted merganser is similar in size and appearance, but is more likely found along the coast. The hooded merganser is listed as “uncommon” and smaller than the common merganser. My journal does include a single sighting in Rocky Brook of a hooded merganser pair on March 8, 2015. 

To date I have yet to get a photo of a merganser, they up and leave as soon as my presence is sensed (and they sense me way before I see them). To remedy this I am trying a couple of things. 

First, I try to have a camera available at The Observatory, ready to snap a picture of not just a merganser, but any interesting wildlife that appears. 

Second, I am making a common merganser nesting box, to be placed it in a big cottonwood tree near The Observatory. Hopefully, one of these years a pair will decide that it is a perfect spot for nest.  

The Cornell Ornithology Lab provides design drawings and placement guidelines related to nesting boxes for various birds. It turns out a box for a common merganser would also service a pileated woodpecker, which kind of make sense since the literature states that mergansers often choose holes in trees made by these woodpeckers. Common mergansers are fairly large birds ( up to 3.5 pounds, 34 inch wingspan) so they need a pretty big tree and hole. 

Maybe an updated version of this blog will include photos of both adult and young mergansers in Rocky Brook. For this to happen there needs to be enough fish in both the Dosewallips and in Rocky Brook to sustain them. 

As they say, “the jury is out” on this. Based on the salmon runs of the past few years, things don’t look too good. 

Yet, I have to be hopeful.

Here is the merganser in the photo at the top. I typically see them as a flash of white before disappearing downstream.

Dennis Lloyd Kuklok

April, 2023

Blog Number 15

Next Blog should appear on June 1.

And, here is a merganser cartoon.

Mergansers are not commonly seen in Rocky Brook on the east side of the Olympic Peninsula of Washington. Adult male common mergansers are occasionally observed in Rocky Brook in the late winter and early spring when they appear to be feeding on emergent salmon.  Adult females with chicks are occasionally observed in early summer. They likely feed, nest and live on the larger Dosewallips river and head up Rocky Brook primarily to feed.

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