Birding in the winter is a case of feast or famine. It’s not uncommon to hike most of the day and practically see no birds at all, then, suddenly, you may notice the trees and shrubs around you are alive with a mixed flock of many bird species. If you’re in the woods, you will probably identify such species as Carolina chickadees, tufted titmice, golden-crowned kinglets, brown creepers, downy woodpeckers and white-breasted nuthatches.
If you watch closely, you will probably find that these winter flocks are led by either the chickadees or titmice. These two nuclear species within the mixed flock average six birds and form around a dominant pair, normally that mated the previous season in that general area. Other members of the population may be juveniles of the dominant pair or other stray adults and juveniles. They will remain within a general range throughout the winter that includes their breeding site as well as several good feeding sites that they will return to numerous times. In fact, some flocks will rotate among four or five favorite feeding sites on a daily basis. It is not uncommon for these chickadee and titmice flocks to return to the same roosting site every night during the winter season.
It has been suggested that the other species tag along with the chickadees and titmice because the vocalizations of these two species enable the others to maintain their small groups. This is especially beneficial for the very small kinglets, which often can survive the winter cold only by huddling in tree cavities overnight. By staying together by listening to the vociferous chickadees and titmice, they are assured of overnight companions. Also, the nuclear chickadees and titmice, being year-round residents, know the good feeding areas. Thus, the winter guests benefit from this knowledge.
Anther benefit of winter flocks is that there is safety in large numbers. By having many eyes around, individual birds can spend more time eating and less time looking for predators. From the perspective of the nuthatch or downy woodpecker, flocking with the very alert and excitable chickadees and titmice increases their awareness of incoming predators and thus adds to their chances of winter survival.
Slightly less than half of our summer residential population of bird species remains in the Appalachian region throughout the winter season. While cold is certainly an issue, finding food is the primary limiting factor for bird survival. Three sources of food fuel the engines of our warm-blooded feathered friends: insects, seeds, and scavenged materials. Some species will remain obligated to being seed-eaters or insect eaters in the winter as they are in the summer season, while others will switch from summer insects to winter seed-eaters. Scavengers, including crows, pigeons and gulls, will remain as generalists throughout the year, feeding on road kills and human dumps in the winter.
The forest mixed-flock described earlier is an insect-foraging flock, even though acorns and beechnuts are also consumed by some of these species. What makes the mixed species work, is that the various species have different feeding habits that allow them to exploit unique niches not used by the other species, allowing community feeding without direct competition.
Seed-eating species of mixed flocks are found in grassy fields where perennial broadleaf and grass seeds dominate. As opposed to the quick moving forest insect-gleaners, the field seed-eaters may spend days in a single field, until the seed resources are gone. Such mixed flocks will include finches, sparrows, mockingbirds and grosbeaks. More common on the piedmont and coastal plain are the extremely large winter flocks of common grackles, red-wing blackbirds and cowbirds, foraging on the waste from agricultural operations, including corn, wheat and soybeans.
Other winter bird species are true to the old saying, ‘Birds of a feather, flock together”. Most of these same species flocks will be seed-eaters. This is apparently due to the localized, but widely spaced food sources required by the selective feeders. Unlike the uniform distribution of insects available to the insect-eaters, the specialized food sources of the seed-eaters makes it more productive for any one species to join up and travel with its own kind to find it’s special seed preferences. This strategy applies to robins, cardinals, northern juncos, grosbeaks and goldfinches.
Winter bird flocks are fairly loosely organized, with individuals joining and leaving on a daily basis. Nor is it uncommon to find sparrows, finches or grosbeaks in separate feeding flocks or in mixed flocks. Furthermore, seed-eaters may accompany woodland insect-eaters. These species will be found hunting among the forest leaf litter, including juncos, white-throated sparrows and eastern towhees. In this scenario, the seedeaters specialize on their food resources without competing with the insect-eaters, while benefiting from the group protection.
Regarding robins, it does appear that they migrate from this area, returning in the spring, but they actually are around all winter. True, the robin population shifts south by several hundred miles in winter, but we still have a winter population in our region that came from breeding sites in PA or NY. The reason we don’t tend to see them is that their winter food source is seeds and berries found in a more forested habitat. Only in spring, when the soil warms and thaws, enabling the worms’ return to the surface, will we see the ‘return’ of the robins to our yards. This normally occurs in March, when the full moon is known by the Native Americans as the ‘worm moon’.
Below is a summary of information gathered from available sources on the typical characteristics of some of our common winter flocking birds.
Carolina chickadee – Moths and their larvae and eggs, acorns and poison-ivy berries are the most important animal and vegetable foods. See above text for more characteristics.
Tufted titmouse – Feed like chickadees, working twigs, buds, and bark for insect egg masses and pupae, also beechnut and acorn mast. Like the chickadee and nuthatch, it is a permanent resident of its territory. Found in flocks of 3 to 6, often being parents and offspring. Very vocal. Winter food is acorns, beechnuts, corn and wild berries. Will also glean branches for insects.
Golden-crowned kinglets – Smallest bird of the winter forest, kinglets migrate to our region and feeds in coniferous trees, constantly communicating with a soft high-pitched trill note. Feeds on insect eggs, larvae and spiders. They are very active feeders, hovering momentarily, as they feed on insects found on branch tips.
Brown creeper – This winter migrant is known for its characteristic foraging habit of alighting at the base of a tree and spirally around it as it ascends, searching for insect eggs and larvae. It is often found singularly or among a mixed foraging flock.
Woodpeckers – Our region is home to six permanent species and one winter guest. The yellow-bellied sapsucker is a winter migrant to our region, responsible for the horizontal series of small holes along the boles of trees, especially tulip trees and apple trees, where they lap sap and trapped insects. While some downy woodpeckers will migrate south, hairys will stay in the same territory. The pileated woodpecker’s feeding habit is notably identified by the large 6” x 8” deep rectangular holes it makes in search of insects, most likely carpenter ants. Only hairy and downy woodpeckers are regular mixed flock participants.
White-breasted nuthatch – This is our only winter bird that climbs down a tree trunk. This enables it to find eggs that ascending brown creepers and woodpeckers might overlook. Winter food is primarily nuts; acorns, beechnuts, hickory nuts and cherry pits. Males and females tend to remain in nesting territory, thus will exhibit monogamy for several years.
Northern junco – Flocks are usually small and can include other birds, especially sparrows. In winter, juncos feed on the ground, taking weed seeds and wild fruit (including ragweed). Often use same wintering grounds each winter. Establishes four or five favorite foraging sites, usually no more than two to three hundred yards apart. Members of these flocks will feed only at these established sites, foraging alone or in groups. Flock members change constantly. Identified in their flight by their gray tails lined on either side with white feathers.
Cardinals – Form loose flocks of about a dozen that feed together. They are non-migratory, spending their entire lives within a few miles of their birthplace. Cardinals are seed-eaters.
Robin – Establishes large flocks, roosting at night in wooded swamps. Feeds on fruits.