by Frank Keim
With its drab olive-green color and white wing bars, the Alder flycatcher seems like an unremarkable bird. It sits almost all day long on high perches in open wet thickets of alder and willow above bogs and beaver ponds, darting out now and then to catch insects in midair or gleaning them from nearby tree leaves.
But when you search deeper into the yearly cycle of these little guys, you’ll discover some truly fascinating things about them. Like the long distances they migrate between their summer breeding ground in Alaska and their winter habitat as far south as the eastern tropical forests of Bolivia and northern Argentina in South America, then back up again to Alaska. There’s also its telltale call repeated over and over, which sounds a little like free beer or three cheers*. And much more.
When these little flycatchers return from South America in May they have no time to spare and quickly establish territories and find mates. The male reacts to rival males by flicking its wings and tail, raising its crest, then chasing the intruder away. Their courtship behavior is not well known but includes active pursuit of the female by the male through the trees.
The female builds a scruffy looking open cup nest low in an alder or willow tree out of grass, bark strips, twigs and rootlets, and lines it with plant down or other soft materials. It usually has ragged threads of grass, moss or cattail fluff dangling from its bottom and sides. This tangle of vegetation serves to camouflage the nest from the eyes of predators. She then gets down to business and begins laying 3-4 creamy white or buff eggs, usually unmarked, and incubates them with help from her mate for about two weeks.
After the eggs hatch, both parents help feed the nestlings for another two weeks, when the young finally feel strong enough to fly on their own. The fledglings then perch on top of a nearby tree and study closely as they learn from their parents how to hunt for insects that happen to be in the neighborhood, and generously fatten up on them so they can leave for South America sometime in August as the insect population begins to wane in Alaska.
The population of Alder flycatchers is declining partly because their migration route takes them through parts of central Canada and eastern U.S. where farmers use a lot of herbicides and insecticides like Roundup and Glyphosate. Both of these are powerful toxins and kill billions of insects every year. Climate change is also responsible for huge decreases in insect numbers because it creates conditions that lead to drought and runaway forest fires that kill billions more insects, thus depriving the birds of their primary food source. And the ravaged landscapes that result do not recover for years. Deforestation in their tropical winter South American habitat is another reason for this decline.
As with the Olive-sided flycatcher, I could not find a Yup’ik name for this little bird. This may be because they’re found only on the eastern edge of the Y-K Delta where there are more and taller deciduous trees in association with bogs and beaver ponds. Since they end up in South America during the winter, however, they do have a Spanish name, Mosquero Alisero, and a French name, Moucherolle des aulnes. Their scientific name, Empidonax alnorum, is from the Greek, empis, “gnat,” and anax, “master;” alnorum is from the Latin, and means “of the alders.” Hence the full meaning, “master gnatcatcher of the alders,” which is where the English common name came from.
*As I mentioned for the Olive-sided flycatcher, the Alder flycatcher’s calls are genetically hardwired, so they don’t change very much. In fact, this trait applies to all flycatchers. This is different from songbirds whose songs are learned and are therefore more varied and much more melodious.
