Get to know Marin’s bug-eating birds

Winter is a great time for attracting birds to your yard. The ubiquitous crowned sparrows have arrived. Year-round goldfinches eat shelled sunflower and Nyjer seed with a far greater appetite than in spring and summer. But there are some winter birds that eat mostly insects and are far easier to overlook, although they are reasonably common and can often be attracted to feeding stations: These include the ruby-crowned kinglet, Townsend’s and yellow-rumped warblers and the hermit thrush.

Ruby-crowned kinglets are probably the most widespread of these birds, but they are incredibly easy to miss. You might hope that a bird named “ruby-crowned” would bear a vivid signpost of identity on its head. You would be wrong. In the great majority of encounters, the ruby crown of the males is entirely invisible, typically revealed only in moments of aggression or agitation. Instead, identify kinglets by their tiny size, the white bar on their wings and their constant jittery movements accompanied by jittery “jid-dit” calls.

The next of the neighborhood bug-eaters to be aware of are our two winter warbler species: the yellow-rumped warbler and the Townsend’s warbler. Yellow-rumps are the more abundant of the two, frequently flocking in open woodlands, parks and neighborhoods. Fairly plain in their winter plumage, close observation will nonetheless detect the namesake yellow rump patches, as well as yellow on the throat and under the wings. Townsend’s warblers are less numerous (they are typically encountered singly), but more striking, with plumage of vividly contrasting stripes of black and yellow.

The last of the subtle winter bug-eaters to start watching for is the hermit thrush, a small brown bird with a spotted breast that bears a superficial resemblance to the fox sparrow, but which can easily be distinguished by its brick red tail and much slighter build. Technically, we do have hermit thrushes in the summer, but those breeding birds are restricted to forests, where they sing one of the most famously beautiful of American bird songs. The Bay Area sees a large influx of hermit thrushes in winter, however, and they can be readily detected in most neighborhoods muttering low “chup, chup” notes from the underbrush.

So those are the birds: kinglets, two winter warblers and hermit thrushes. At least some of these are present in almost every yard in Marin in winter, but most people overlook them. The obvious way to stop making that mistake is to attract them to specific, visible parts of your yard — or to watch for spots that they are already visiting. Any bird can visit a birdbath. Hermit thrushes and yellow-rumped warblers can eat berries, joining other birds like cedar waxwings, bluebirds and robins in both native and ornamental plants.

But you can also offer food directly to these birds. Despite their general inclination towards eating insects, winter’s cooler temperatures and relative scarcity of prey encourage these birds to visit our offerings when needed. Townsend’s warblers will join some year-round insect-eaters like bushtits and bluebirds in eating shelled sunflower chips. Suet is an even more useful offering for bug-eaters. These cakes or balls of fat and other ingredients are eaten by both warblers species and ruby-crowned kinglets as well as a host of year-round birds such as woodpeckers, titmice and chickadees. Suet comes with several important benefits, most notably its lack of mess and its ease of squirrel-proofing with spicy, hot pepper flavors that taste-sensitive mammals find unpleasant to eat.

A final offering is reserved for the more adventurous feeders of birds: live mealworms. These slow-moving beetle larvae can be offered in any smooth-sided dish or simple hanging “treat” feeder, where they will be wildly appreciated by all four of the winter bug-eaters — as well as the great majority of birds in your yard. I’ve heard of many birds visiting mealworm feeders that rarely, if ever, visit feeders for other foods, including black phoebes, mockingbirds and robins along with more everyday feeder visitors.

Offer shelled seeds, suet and mealworms, or offer nothing but water, berries and attention — in either case, these birds are waiting for your discovery: kinglets with hidden crowns, warblers in their silent season and hermits come down from the mountains to seek shelter in your town.

Jack Gedney’s On the Wing runs every other Monday. He is a co-owner of Wild Birds Unlimited in Novato and author of “The Private Lives of Public Birds.” You can reach him at jack@natureinnovato.com.