Bohemian Waxwing tops Kimberley’s bird count

1845 individual birds counted in Kimberley for this year's count

The Chestnut-backed Chickadee was a common sight at Kimberley feeders.

The Chestnut-backed Chickadee was a common sight at Kimberley feeders.

Daryl Calder

Rocky Mountain Naturalists

Six intrepid naturalists knew that birding would be quite good in Kimberley. January 2, 2016, a chilly, calm, grey day was uncomfortable for humans but did not deter the birds. To generate body heat, birds need to be constantly searching for food during daylight hours in order to survive the long winter night. With the help of 4 feeder watchers, a relatively large number of birds were counted for the benefit of the 116th annual Audubon Christmas Bird Count. Birders investigated grasslands, forests, rivers and streams, wild, rural and urban areas.

The species list was longer than average, including 19 types which have been observed on virtually all of the 24 Kimberley counts. Chestnut-backed Chickadee, Pacific Wren and Varied Thrush have only been spotted a couple of times. Even though the Cranbrook and Kimberley count areas are not far apart, eleven species detected in Kimberley this year were not found in Cranbrook and vice-versa. Adding eleven to each count indicates that about 60 types of bird can survive the winter in this part of the East Kootenay. The ‘eleven’ are an assortment of waterfowl, raptors, thrushes and winter finches which are not particularly uncommon in either area.

One little non-migratory bird was seen on both counts. The very attractive Chestnut-backed Chickadee will move up to higher elevations in late summer, moving back to lowland forests following heavy snowstorms. They prefer dense, wet, coniferous forests along the Pacific coast between Southern California and Alaska, and a zone which reaches into our part of the Rocky Mountains. They occur in a wide variety of forest types, including deciduous woodlands and brushy streamsides. In urban, suburban and rural areas, where extensive trees and shrubs are present, they are commonly seen at backyard feeders. Active, sociable and noisy as any chickadee, you’ll find these birds at the heart of foraging flocks moving through tall conifers, with titmice, nuthatches, and sometimes other chickadee species.

A cavity nester, the Chestnut-backed Chickadee uses a lot of fur in making it’s nest, with fur or hair comprising half of the material in the hole. Rabbit, coyote or deer hair are most common, but hair from skunks, cats, horses or cows appears in nests as well. The adults make a layer of fur about one half inch thick to cover the eggs when they leave the nest.

Cavity nesting birds tend to have better success than open-cup nesters, but that doesn’t mean they are immune to predation. Nests get attacked by predators including mice, squirrels, weasels, snakes and black bears.

Males take the first step in choosing nest sites, approaching a possible location while the female watches. Later, the female decides on the site, enters the cavity, and accepts pieces of vegetation brought by the male. Nest sites can be holes in rotted trees, stumps and posts soft enough for the chickadees to excavate themselves, or old woodpecker holes. Chestnut-backs will use nest boxes or natural cavities 1-12 feet above ground. Nest building takes 7-8 days, and the thickness of the finished product can vary in height from 1-6 inches. Females build the nest on their own, starting with a foundation of moss and strips of bark, particularly incense cedar when it’s available. The nest’s upper layer consists of animal hair woven with strips of bark, grass, feathers and sometimes textile fibers. Finally, the thin, warm flap is added.

These chickadees eat about 65% insects, feeding their young mostly caterpillars and wasp larvae. To a lesser extent, they also eat seeds, berries and fruit pulp.

Chestnut-backed Chickadees are common across their range, but populations have been gradually declining since 1966. At 1% per year, the result is a cumulative decline of about 42% according to the North American Breeding Bird Survey.

Forest management practices which remove potential nest sites, can make it difficult for these little birds.

Another handsome denizen of the dark, wet, mature forests of the Pacific Northwest has been observed lately. In winter, the Varied Thrush may be found in parks, gardens, lakeshores, and riparian areas where fruit and berries are abundant. In fact, this shy bird has apparently discovered the benefits of feeders around Cranbrook and Kimberley.

These thrushes forage for insects in summer and switch to berries and seeds in winter. This short-distance, partial migrant, may travel south in winter, sometimes leap-frogging over southern breeding populations. In many winters, a few Varied Thrushes move erratically and appear in the Midwest and Northeast, far out of their normal range.

During breeding season, these thrushes eat insects and arthropods hidden in leaf litter. They forage by seizing dead leaves in their bill and hopping backwards to clear a spot of ground before examining it for prey. Foraging Varied Thrushes can be seen on the ground in small openings, but look for singing birds at higher perches in the understorey and lower layers of the forest. Louis Agassiz Fuertes, a twentieth century bird artist, described the Varied Thrush’s simple, contemplative song “as perfectly the voice of the cool, dark, peaceful solitude which the bird chooses for its’ home as could be imagined”.

Long-term data has shown that populations go up and down on a 2 year cycle. They are often aggressive to each other and other bird species. At feeders, males sometimes defend small feeding territories. The only time Varied Thrushes flock with other species is when they occasionally forage for berries or earthworms on lawns with American Robins.

Females probably choose where to place the nest, usually in the understorey of a mature forest, often in a spot surrounded by old nests. The female gathers nest material, weaving an outer layer of twigs. She adds a middle layer of rotten wood, moss, mud or decomposing grass which hardens into a dense cup 4 inches across by 2 inches deep. Finally, she lines the cup with fine grasses, soft dead leaves and fine moss. The poorly concealed nest, close to the trunk of a small conifer, is then draped with pieces of green moss.

According to the North American Breeding Bird Survey, Varied Thrushes are fairly common but their populations have declined by 62% since 1966. The 2014 ‘State of the Birds Report’ listed them as a common bird in steep decline. Logging and forest fragmentation can cause habitat loss; they tend not to live in forest patches smaller than about 40 acres. Around human habitation, varied Thrushes have proven very vulnerable to window strikes, as well as predation by domestic and feral cats and collisions with cars. Varied thrushes may benefit from reserves that have been established to protect the Northern Spotted Owl.

The Kimberley List, 48 Species, totalling 1845 individuals

Mallard    1

Common Goldeneye    15

Wild Turkey    4

Bald Eagle    1

Red-tailed Hawk    1

Rough-legged Hawk    1

Wilson’s Snipe    2

Rock Pigeon    25

Eurasian Collared-Dove    5

Mourning Dove    2

Northern Pygmy-Owl    1

Downy Woodpecker    31

Hairy Woodpecker    19

American Three-toed Woodpecker    1

Northern Flicker    19

Pileated Woodpecker    7

Steller’s Jay    17

Blue Jay    11

Black-billed Magpie    14

Clark’s Nutcracker    51

American Crow    49

Common Raven    93

Black-capped Chickadee    95

Mountain Chickadee    80

Chestnut-backed Chickadee    6

Red-breasted Nuthatch    32

White-breasted Nuthatch    2

Brown Creeper    3

Pacific/Winter Wren    1

American Dipper    2

Golden-crowned Kinglet    4

Townsend’s Solitaire    2

American Robin    2

Varied Thrush    3

European Starling    4

Bohemian Waxwing    490

Snow Bunting    65

American Tree Sparrow    6

Dark-eyed Junco    12

Song Sparrow    2

Pine Grosbeak    87

House Finch    32

Red Crossbill    68

Common Redpoll    311

Pine Siskin    2

American Goldfinch    11

Evening Grosbeak    78

House Sparrow    55

Submitted by Daryl Calder on behalf of Rocky Mountain Naturalists