Some summer birds can tough out colder weather
Vireos, warblers, swallows, and hermit thrush are normally associated with the summer, but occasionally they straggle behind the fall migration or decide to spend the winter. Although they surprise us, especially when we see them on snow-covered bushes and trees, these species and many other summer birds, do have the ability to tough out colder weather. Look for them at coastal sites, in wetlands, and places where there are fruit-bearing plants.
At Hammonasset State Park in Madison, birders reported a white-eyed vireo in early December, a pine warbler, and a wayward tree swallow in late November. White-eyed vireos, which normally live on caterpillars, flies, moths, leafhoppers, and small spiders, can sustain themselves on wild fruits should they fall behind the migration south and encounter unexpected cold weather. Pine warblers, known to arrive very early in the spring, are hardy warblers able to feed on pine seeds during the colder months. However, the report of a neotropical tree swallow is amazing. Believe it or not, they survive cold spells feeding on clam shells and bits of plants.
Many birders are also finding yellow-rumped warblers where there are large concentrations of wild fruit. The yellow-rumped warbler is 5 to 6 inches long, has a thin bill and slightly notched tail. The male is blue-gray with a white throat, belly, and has black streaking on the back, a black face patch, and two white wing bars. They have yellow spots on the crown, shoulders, and rump. In the fall, they have some brown plumage and less yellow.
Yellow-rumped warblers are insectivores during the summer, but they switch to fruit during the colder months. They breed to our north, where spruce is abundant and up into the boreal regions of Canada. Typically, birders see them during the spring migration in May as they travel through, but because they can survive on wild fruit, they sometimes linger here into the winter. In fact, large numbers of them winter over as far north as the mid-Atlantic states.
Similarly, the hermit thrush, an insectivore during the breeding season, converts to a diet containing some fruit during the winter. Hermit thrush are not likely to show up at your suet feeder, but may be seen feeding on wild berries. Like the robin, which winter over in large numbers, they are often found deep within the wetlands. Connecticut is at their most northern limit during the winter, when most hermit thrush migrate much farther south. They are, however, known to leave their breeding habitat in northern New England later than other kinds of thrush. So it is not uncommon to see a few at this time of year.
It is uncommon for the Baltimore oriole to remain in Connecticut during December. A few were reported recently in southern Connecticut. Two common yellowthroats were
seen in Silver Sands State Park (Milford). These tiny yellowish warblers have a black face mask (males) and love to feed on insects in deep brushy wet thickets. They too can survive the cold by feeding on fruit.
Hopefully, the white-eyed vireo, tree swallow, and common yellowthroats have all headed south by now: I have my doubts whether they can survive the true winter weather as well as the yellow-rumped warbler and hermit thrush, which are better equipped to make it here year-long. Perhaps, those beautiful Baltimore orioles have found a reliable supply of suet — otherwise they must heed the call south, too.
Robert Tougias is a Colchester-based birder. His new book, “Birder on Berry Lane,” is available online now and in stores March 2020. You may ask him questions at roberts90gtias@yahoo.com