It is human nature to value the unusual or the rare more so than the common and the everyday. Birders are no different. Birders are always on the lookout of the “rare” birds; if you stumble onto a birding party, the question most often asked is some variation of Have you seen anything good? In this case, “good” means “rare”; no one asks or cares if you’ve seen the common species.
There are “rare” birds, and then there are rare birds. This second class encompasses birds that are rare everywhere. In North America, a bird that ranges on the West Coast that somehow shows up on the East Coast is considered “rare” and East Coast birders will come in droves to see it. But that doesn’t mean that particular bird is rare everywhere – the “Oregon” junco is “rare” in Ontario, but is commonplace in Nevada.
There is another word for that second class of rare bird. The word is endangered.
This kind of rare bird is rare everywhere it occurs; there just aren’t that many of them. The reasons a bird becomes endangered are many; most often human-related, but not always. And because there are so few of them, having the opportunity to see an endangered species is one that you never forget.
I had just such an opportunity this past weekend, when I joined Birds Korea member Jason Loghry on a survey near the city of Naju-si. We were surveying the population of scaly-sided merganser, a species listed as globally endangered by the IUCN (International Union for the Conservation of Nature). By the most recent estimates, there are only about 2,500 adult scaly-sided mergansers left in the world, most of which are found near where the borders of China, North Korea, and Russia, meet.
Out of concern for this species, I will not reveal where exactly we found these birds. This species is excessively shy and wary of humans, and is easily disturbed. Even to observe these birds, we had to be very quiet and patient, and even then sometimes the birds would take to the air and fly off to another location. The purpose of this post is to raise awareness of this rare bird, not to create a crowd of (likely well-meaning) observers who may or may not maintain the same level of care and respect that the species deserves and requires to continue existing.
The scaly-sided merganser closely resembles the common merganser, which is far more common (as the name implies) and familiar to the average person. Indeed, I had never even heard of scaly-sided merganser until I moved to South Korea, and even then I never expected that I would actually see one.
Males have a long, shaggy crest, which the common merganser males lack. Females are harder to differentiate, as they closely resemble the females of common merganser. The key distinguishing characteristic of the species is a patch of scale-like feathers on the flanks and rump of the bird; these feathers are what give the species its name. The birds also have a small yellow tip on their bills, though this is rarely visible in the field.
This species is a wintering bird in South Korea, and selects waterways that meet very stringent criteria during the winter months. The river cannot be too deep or too wide. Often times they prefer gravel-bottomed riverbeds with large boulders or gravelly “shingles” where they can locate food. Even finding this particular habitat, the onset of winter and the resulting freeze-up often means that the birds must relocate to other rivers until the return of spring.
It was a rare privilege to find and observe these birds. Jason and I had the good fortune to find six of them along the survey route. We could watch them feed and preen, and interact with other species on the water. In a comical display, a group of five scaly-sided mergansers expressed their displeasure at a nearby grey heron by repeatedly bobbing their heads in and out of the water as they approached the heron.
For more information, I encourage you to check out Birds Korea’s Key Species page.