ALWAYS IN SEASON: Yellow-rumped warbler provides good introduction to the warblers
The yellow-rumped warbler is aptly named, but the rump is only one of five spots of yellow on this little bird. The others are at the top of the head, the throat and on either side of the breast.
Actually, these are more like splashes than spots, and they stand out brilliantly against the bird’s otherwise more subdued plumage.
The splashes render the bird instantly recognizable whether it is perched in a treetop, visiting a suet feeder or foraging on the ground.
For this reason alone, yellow-rumped warblers make a good introduction to the warbler tribe, but there are other reasons as well.
One is that the yellow-rumped warbler is always the vanguard of warbler migration. It is a hardy bird that nests across the forest belt in the northern United States and Canada. This belt reaches northeast Minnesota, and there is an island of it in the Turtle Mountains straddling the international border about halfway across the state. There are records of breeding just across the border in Manitoba.
The birds also nest in an isolated stand of ponderosa pines in the Badlands near Amidon, N.D. — relatively near in the context of distance in southwest North Dakota. This is the so-called Audubon’s warbler, which occurs across the Mountain West.
Audubon’s lacks the yellow splash on the rump but is otherwise pretty much identical to the yellow-rumped warbler. The two are so closely related genetically that they are considered a single species today.
Not long ago, the yellow-rumped warbler was known as “myrtle” warbler, and bird guides printed before 1975 or so list them as separate species.
Birders are both grateful for the yellow-rumped warbler and a little annoyed by it. It is a beautiful bird, and its appearance is a reliable indication that winter is, at last, finished. Most years, the first yellow-rumped warblers appear in Grand Forks about the end of March or very early in April.
They were late this year.
The birds are annoying because of their abundance.
Warbler migration is eagerly anticipated among birders, and yellow-rumped warblers provide a kind of aperitif. They whet the appetite.
They also distract the attention.
Yellow-rumped warblers far outnumber any of the other migrant warbler species here, and so birders lose a lot of time looking at what is a common bird instead of studying the other, equally colorful and far less common warblers that pass through.
This frustration can be reduced somewhat by two little tricks. The first is to instantly recognize the pattern of the yellow splashes. Other warblers have yellow highlights, too, but none in the same pattern as yellow-rumped warblers.
The second trick is to learn the voice of the yellow-rumped warbler. Yellow-rumped warblers are relatively noisy, giving rather harsh and emphatic clicks, often rendered as “tchip” or “tsee.”
Males sing, but the song is uneven and varied. The most important element is a repeated “twee-twee-twee” sound that can be flat or sometimes rising or falling at the end.
Find and listen
This is vague, I know; the best thing to do is to find yourself a yellow-rumped warbler. That shouldn’t be difficult this week. Try your backyard first. Or visit a park or shelterbelt.
Identify the yellow-rumped warbler. Appreciate its beauty. Then listen and commit the sound to memory.
This will allow you to dismiss the yellow-rumped warblers and concentrate on other species once migration erupts, which should happen within the next fortnight.
It’s also worth watching yellow-rumped warblers to learn their behavior, which is typical of most warblers — but not all, note well.
Warblers are mostly insect eaters, which explains why they migrate later than the sparrows, which subsist on seeds.
Warblers pick insects off bark and buds, so they often move about in treetops. They also flit out from exposed branches to take insects on the wing, a behavior called “fly-catching.”
They occasionally go to ground where they pick up insects, but this is unusual and usually occurs during bad weather that produces difficult flying conditions and forces the birds to interrupt migration.
This produces a fall, similar to the fall of sparrows that occurred two weeks ago.
In all, about 20 species of warblers can be expected here in spring migration, almost all of them are northward bound, Only a few warblers species nest in the area.
Jacobs is a retired publisher of the Herald. Reach him at email@example.com.