Chestnut-backed Chickadee - Conifer Connoisseur
Hanging upside down from a Douglas Fir cone, a diminutive masked songbird with rich chestnut coloring on its back and sides feeds on the cone’s seeds. This smallest of North America’s seven chickadee species, the Chestnut-backed Chickadee derives its name from this coloring. Yet, the chestnut hue can be difficult to spot in low light, especially when the bird is actively foraging high in a canopy of dense conifer branches. Unlike its relatives, the Chestnut-backed Chickadee doesn’t sing a whistled song; instead, it gives high-pitched call notes that can easily be mistaken for those of the Golden-crowned Kinglet, a species that often joins it in mixed species flocks during the winter.
The Chestnut-backed Chickadee is well adapted to the coniferous forests along the western slope of the Pacific Northwest. Its primary coastal range extends in a narrow band from southern coastal Alaska to approximately the Los Angeles area. An isolated inland population of birds is centered in northern Idaho and eastern British Columbia, extending into neighboring states. According to the American Bird Conservancy's Bird Library, the Chestnut-backed Chickadee’s population is decreasing, with an estimated total of around 12 million.
Black-capped Chickadee - City Dweller
Across much of the Chestnut-backed Chickadees range, the Black-capped Chickadee’s range overlaps. The Black-capped Chickadee has a much broader range, spanning much of the northern United States and southern Canada, and extending farther into Alaska. Unlike Chestnut-backed Chickadee, the Black-capped Chickadee has a stable population, currently estimated at around 39 million.
Coexisting Chickadees in Edge Habitat
According to research by Smith (1967) conducted on the University of British Columbia campus, Chestnut-backed Chickadees are more likely to forage in coniferous trees, while Black-capped Chickadees tend to favor deciduous trees. Smith also found that Black-capped Chickadees typically forage closer to the ground than Chestnut-backed Chickadees. This behavioral difference may help explain why Black-capped Chickadees are more frequently documented in iNaturalist. In Seattle, where both species occur, iNaturalist data shows significantly more observations of Black-capped than Chestnut-backed Chickadees.
iNaturalist data analyzed by Di Cecco et al. (2021), from 2008 – 2019, found that birds made up 7 of the 10 most observed species on the platform. Of these seven bird species (Mallard, Great Blue Heron, Canada Goose, Red-tailed Hawk, House Sparrow, Great Egret, and American Robin) only two are classified as songbirds. Songbirds are generally more difficult to document, track, and identify, especially when compared to larger, more visible birds. iNaturalist observations are also biased toward urban-dwelling species, as the majority of iNaturalist contributors live in urban areas.
Protected Forests and Dead Standing Trees
Although Chestnut-backed Chickadees will readily use nestboxes, as secondary cavity nesters they typically rely on dead standing trees for nesting. Outside of protected areas such as Olympic National Park, most Olympic Peninsula forest plantations are actively managed, meaning that critical habitat features, such as dead standing trees, are often missing. Plantation trees are usually even-aged, often limited to a single species (typically Douglas Fir), and are harvested on roughly a thirty year rotation. Access to suitable nesting sites, along with the availability of insects and caterpillars needed to feed their young, are two habitat features that will largely determine the long-term success of Chestnut-backed Chickadee populations.
Winter Survival
In the fall, both species of chickadee, along with Red-breasted Nuthatch, frenetically cache black-oiled sunflower seeds in both natural and urban settings. Seeds may be tucked into cracks, between siding, under roof shingles, around windowsills, and in gutters. Some seed feeders, especially those with minimal space between the roof and seed tray, are ideal for chickadees, as they make it harder for larger birds to access the food.
Roosting boxes are essentially upside-down nestboxes with the entrance hole near the bottom rather than the top of the box. Inside, small perches provide space for birds to huddle together and retain warmth during extremely cold weather. While winters on the Olympic Peninsula are generally mild, occasional Fraser Valley systems bring frigid temperatures. Although roosting boxes are not intended for nesting, that hasn’t stopped a Bewick’s wren from using one as a nest site.
Native Plants and Nestboxes
While both chickadee species use the habitat in my small urban yard, a Chestnut-backed Chickadee pair typically inhabit the entire backyard during the nesting season. In recent years, they have successfully raised at least three clutches in the backyard nestbox. The backyard’s proximity to mature coniferous and deciduous trees, including Coastal Redwood, Grand Fir, Western Red Cedar, Douglas Fir, Bigleaf Maple, and Red Alder, provide valuable food resources. Nestboxes have been placed at a height of fifteen feet over doorways in both the front and the backyard. The Washington Department of Fish and Wildlife recommends nestbox entrance holes no larger than 7/8 of an inch tall for chickadees, Violet-green Swallow, and nuthatches. An oval or diamond-shaped entrance hold to the nestbox helps to prevent invasive House Sparrows from taking over the box.
The front nest box has an oval size nest hole that has successfully attracted Violet-Green Swallows. However, House Sparrows are a serious threat to all cavity nesting birds. Invasive sparrows are notorious for acting aggressively around nestboxes, often attacking or displacing native birds. This year, a male House Sparrow was the prime suspect in the death of a female Violet-green Swallow. After she and her mate repeatedly chased the sparrow away from her nestbox, I found her dead on the pavement in front of the nextbox moments later.
Chestnut-backed Chickadees build soft, tidy nests composed primarily of mosses. Once abandoned, these nests become valuable shelters for overwintering queen bumblebees, which are also important to support. As year-round residents, Chestnut-backed Chickadees begin nest building early in the spring, often before migratory songbirds return. To successful fledge a nest of chicks, chickadees require over 6,000 moth caterpillars, which they source from native trees, shrubs, and perennials such as Vine Maple, Douglas Maple, Shore Pine, Willow sp., Oceanspray, Salal, Kinnikinnick, Stinging Nettle, Pearly Everlasting, Western Bleeding Heart, Lomatium sp., Lupine sp., native violets, and native grasses. I have planted all of these caterpillar host species around my yard. The only time of year chickadees tend to be absent is immediately after the nestlings have fledged, but by late summer, they always return.
