Birds of the Month: the Winter Warblers

Yellow-rumped Warbler and Townsend's Warbler

Yellow-rumped warbler by S. HuntYellow-rumped warbler eating mealworm - local photo by S. Hunt

Warblers evoke high passion from many birders—a passion often opaque even to sympathetic, but more casual bird lovers. In the eastern part of the country, spring warbler migration is the most thrilling part of the year for birdwatchers, with the treetops suddenly filled with an influx of newly-arrived and soon-to-depart species—colorful, active, challenging, gone. We have fewer warbler species overall in the west, and that group is further winnowed down in winter when most insect-eating birds head south, leaving us with two main species which pass the winter with us: the yellow-rumped warbler and the Townsend’s warbler.

Townsend's Warbler - Theresa Fisher

Townsend's Warbler eating suet
Local photo by Theresa Fisher

Warbler Basics

  • Warblers are small birds, many of them with some yellow in their plumage. But warblers are very different from our other small yellow birds, the goldfinches. If you've got a flock of them sitting on your seed feeder, they're finches. If you see one constantly in motion, darting under leaves and between branches in pursuit of insects, that may be a warbler.
  • Since warblers are primarily insect-eaters, they are never our most abundant feeder birds. When prey is scarcer, however, as will happen in the cold of winter, they can sometimes be lured to suet, mealworm, and hulled sunflower feeders, as well as birdbaths.
  • Since these two species are essentially winter birds in our area, you probably won’t hear them sing much. But as a whole, warblers are not necessarily particularly melodious despite their name.

Yellow-rumped Warbler

  • Yellow-rumped warbler - S. Hunt

    Yellow-rumped Warbler eating Bark Butter
    Local photo by S. Hunt

    Yellow-rumps (or butter-butts as they are sometimes affectionately called), are most easily recognized by that very feature: a yellow rump patch, which may be partially obscured by their wings when perched. They also have yellow under their wings and on their throats, though with the range of females, young birds, and non-breeding plumages your main impression of some birds from some angles will be of an overall light gray-brown. Watch closely and the yellow rumps will be revealed.
  • The most hardy and widespread warbler in North America, these guys can handle cold (they are the only winter warbler in much of the East) and insect-deprivation (they are the rare warbler that will eat berries). Locally, they can be found more or less all over the place in winter, as well in select higher elevation forested areas on Mt. Tam during the spring-summer breeding season. 
  • Our favorite 1920s ornithologist, William Leon Dawson, summed up the yellow-rump’s toughness and adaptability like this:

Without tools or furnishings, without connections or backing, without so much as a hand-bag in which to keep a few cherished belongings, this brave young Argonaut faces the world… “Ho ho! Who cares! The world is mine. Not a tree, but I shall explore it; not a canyon, but I shall quaff water from its depths; not a mountain, but I shall mock at its glaciers; not a tempest, but I shall know how to escape its fury. Ho ho!” And so this tiny warbler, penniless and homeless, threads mazes which no surveyor has ever chained, scales heights which no aneroid has ever measured, sleeps in a hundred and forty different beds, from the lowly weed to the fir tree’s loftiest pinnacle, lunches at ten thousand counters, and comes back to us winter by winter, artless, unspoiled, cheerful, and courageous.

  • There are two main forms or races of yellow-rumps, which are sometimes considered to be two separate species. Our more common race, known as the Audubon’s warbler, has a yellow throat. The other race, the Myrtle warbler, is the common species in the east, but can also be found here in winter in lower numbers. They have white throats.

Townsend's Warbler

Townsend's WarblerTownsend's warbler at bath - local photo by Gary Walter

  • Townsend’s Warblers are one of our most striking and distinctive birds. Males have a vividly contrasting black and yellow pattern on their face, with a black throat. Females still echo this distinctive pattern quite clearly, but are duller overall and have pale yellow throats.
  • They breed in the Pacific Northwest, between Alaska and Oregon, and then have two separate wintering grounds: one along the temperate California coast and another in Mexico and Central America.
  • As with yellow-rumps, Townsend’s warblers are sometime visitors to feeders offering suet, mealworms, or hulled sunflower chips.

Townsend's Warbler eating mealworms
Local photo by Angela Casey

  • Townsend’s warblers were named after John Kirk Townsend, an ornithologist who went on one big adventure to the west (and onward to Hawaii) back in the 1830s. He described the expedition in his quite engaging travel diary, published with the catchy title The Narrative of a Journey across the Rocky Mountains to the Columbia River and a Visit to the Sandwich Islands. It was tough work advancing science out here back then, requiring a long, cold, wet, hungry, dangerous trek with myriad threats to one's painstakingly collected specimens. For example, Townsend writes:

On returning, I was surprised to find Mr. N[uttall] and Captain T. picking the last bones of a bird which they had cooked. Upon inquiry, I ascertained that the subject was an unfortunate owl which I had killed in the morning, and had intended to preserve, as a specimen. The temptation was too great to be resisted by the hungry Captain and naturalist, and the bird of wisdom lost the immortality which he might otherwise have acquired.


Thornburg had been killed this morning by Hubbard, the gunsmith… This Thornburg was an unusually bold and determined man, fruitful in inventing mischief, as he was reckless and daring in its prosecution. His appetite for ardent spirits was of the most inordinate kind. During the journey across the country, I constantly carried a large two-gallon bottle of whiskey, in which I deposited various kinds of lizards and serpents and when we arrived at the Columbia the vessel was almost full of these crawling creatures. I left the bottle on board...and on my return found that Thornburg had decanted the liquor from the precious reptiles which I had destined for immortality, and he and one of his pot companions had been happy upon it for a whole day.

Sometimes, it can feel like naming birds after people is a rather empty gesture to some forgotten person’s vanity. But once you know a little of this man’s story, his deep love for birds and science, and his strong general optimism, “Townsend” begins to feel rather more meaningful.  

Yellowthroat - JanetandPhilBonus Warbler: Common Yellowthroat

We actually have one more, atypical warbler species that is found here not only in the winter, but all year round, albeit in reduced numbers from their winter peak: the common yellowthroat. Unlike our other warblers, including both the two above and our summer species, yellowthroats do not forage for insects in woodland and forest trees, giving observers the classic birder's ailment known as "warbler neck." Instead, yellowthroats are residents of marshes, skulking amongst the freshwater cattails or dashing down under the salt marsh pickleweed. Females are a relatively muted yellow, but males like this one have a striking black bandit mask. Look for them in marshes and wetlands around the county; probably the easiest place to see them locally is in the cattails that greet you in the first pond at Las Gallinas Ponds in San Rafael. 

Photo by JanetandPhil on Flickr.

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