BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Parus atricapillus | Black-Capped Chickadee 



TIMING OF MAJOR LIFE HISTORY EVENTS : 
Pair Formation: The peak period for pair formation is fall and is
associated with winter flock formation; winter flocks consist largely of
mated pairs.  Even very young black-capped chickadees form pair bonds at
this time.  A few pairs are formed in winter following mortality of
high-ranking members of the flock, and occasionally floaters
(low-ranking individuals unattached to a mate or a flock) establish new
pair bonds in spring [30,31].

Territory Establishment:  Territories are established in spring, during
winter flock break-up; this period varies with area, year, and other
factors.  Breeding territory boundaries are usually established 5 to 7
weeks before onset of egg-laying [30,31].

Nesting:  Both the male and female excavate the nest hole, but the
female builds the nest.  The cup-shaped nest consists of cottony plant
fibers, hairs, wool, moss, and leaves, and is lined with hair, plant
down, wool, and feathers [12].  

Clutch:  Eggs are laid from early April to mid-July depending on spring
weather and food availability [30].  Usually 1 egg is laid per day; the
average clutch size is from 6 to 8 eggs, ranging from 5 to 10.  Eggs are
incubated for 12 to 13 days by the female, who is fed by the male [38].
All eggs usually hatch within 12 to 30 hours of each other, usually in
the order laid [31]; nestlings are present from early May to late July
[30,31].

Development of Young:  Black-capped chickadees are altricial; newly
hatched young are blind and nearly naked.  They have pinfeathers by
about day 9, and usually fledge on day 16.  When nests are disturbed,
fledglings may leave the nest early, sometimes as early as 12 days.
Fledglings are fed by the parents for 2 to 4 weeks (3-4 weeks is
typical) [30,31].

Longevity:  Age at first breeding is typically less than 1 year,
although some individuals may not breed until they are 1 or 2 years old.
The average lifespan of black-capped chickadees is approximately 2.5
years; however, 5-year-old birds were not uncommon in northwestern
Connecticut [17].  The longest lived black-capped chickadee on record
was at least 12 years 5 months at the time of last banding [31].

Mortality:  Black-capped chickadees are fairly cold hardy; the majority
of black-capped chickadee mortality is believed to be caused by winter
malnutrition, which reduces the ability to withstand cold weather and
resist disease.  There have been few major outbreaks of diseases in
black-capped chickadee populations and there are relatively few nest
parasites [31].

Wintering:  Wintering flocks of black-capped chickadees usually consist
of four to eight individuals [9].  Black-capped chickadee residence in
cold climates is made possible by night torpor, a regulated hypothermia
which allows black-capped chickadees to survive cold nights with minimum
energy loss [31].

Seasonal Movements:  Long-distance movements are usually only undertaken
by black-capped chickadees less than 1 year old.  However, large numbers
of black-capped chickadees emigrate at irregular intervals of about 2
years.  These movements are more properly termed irruptions than
seasonal migrations.  Factors influencing irruptions, particularly in
the eastern portions of the black-capped chickadee range, include
fluctuation in northern seed crops and unusually high recruitment rates.
Fall movements tend to be south or southwest; spring movements are
usually northward but are sometimes aimless [31].  Movement over water
is avoided or undertaken only with great hesitation [30,38].


PREFERRED HABITAT : 
Black-capped chickadees prefer relatively open sites near deep woods
[6].  They are usually more common near edges, but also occur in the
interior of wooded tracts [31].  In Iowa most observations of
black-capped chickadees were in floodplain woodlands and scrub; fewer
black-capped chickadees were observed in upland woodlands, wooded edges,
and savannah (in descending order of numbers of observations).
Black-capped chickadee observations were positively correlated with
sapling and tree species richness, sapling and tree size, and vertical
patchiness.  There was a negative correlation with vine density and with
snag hardness [32].  In Saskatchewan black-capped chickadees were found
in aspen (Populus spp.) groves larger than 0.5 acre (0.2 ha) in area,
and did not occur in smaller groves [15].  In Montana foliage-insect
feeders including black-capped chickadees were observed most often in
uncut forests.  Black-capped chickadees fed primarily where foliage
canopy was well developed above 26.4 feet (8 m) [24].

Riparian communities are important to black-capped chickadees and other
gleaners (birds which search vegetation for stationary prey).  Emerging
aquatic insects are a particularly valuable food for gleaners.  Mayflies
and stoneflies spend most of the daylight hours resting on low
vegetation near the stream channel.  The density of gleaners (in this
area black-capped chickadees were the most abundant gleaners) is
positively correlated with emergence rates of aquatic insects [10].

In Colorado black-capped chickadee nest site selection was positively
associated with density of small trees; in Missouri and Tennessee,
black-capped chickadees are reported to prefer small trees and young
open forest [28].


COVER REQUIREMENTS : 
Nesting:  Black-capped chickadees excavate holes in soft decayed wood
and also use existing cavities (but usually only if there is material to
be excavated) [30,31].  Dead standing trees greater than 4 inches (10
cm) dbh are used for nesting and feeding [6].  In Illinois nests were
found in cavities of stubs (broken off snags).  The stubs were usually 5
to 6.6 feet (1.6-2 m) tall and 4.3 to 5.1 inches (11-13 cm) in diameter
[41].

Common nest sites are stubs of gray birch (Betula populifolia) or paper
birch (B. papyrifera) [12], but almost any early seral species with soft
wood may be used; the particular tree species favored depends on the
region.  Most of these trees occur as living trees in early seral
stages, are short-lived, and persist into intermediate seral stages as
decaying snags [40].  For example, Odum [23] reported that of 18
black-capped chickadee nests he observed in upstate New York, 4 were in
pin cherry (Prunus pensylvanica), 3 in paper birch, 3 in American beech
(Fagus grandifolia), 2 in yellow birch (Betula alleghaniensis), 2 in
willows (Salix spp.), 1 in basswood (Tilia americana), 1 in sugar maple,
1 in white ash (Fraxinus americana), and 1 in an apple tree (Malus spp.)
[40].  In Vermont northern hardwoods forests, most black-capped
chickadee nest trees were in an advanced state of decay with soft outer
wood.  Most nests were in trees that were shorter than neighboring
non-nest trees, but no smaller in diameter [26].  Nest trees used by
black-capped chickadees in northwestern Montana western larch (Larix
occidentalis)-Douglas-fir (Pseudotsuga menziesii) forests averaged 8
inches (20 cm) dbh and ranged from 4 to 12 inches (10-30.5 cm) dbh.
This was the smallest average diameter used by any of the cavity-nesting
birds observed [21].  Most nests were in broken-topped larch trees [20].
In Iowa 92 percent of black-capped chickadee nests in riparian
communities were in snags, 4 percent were in dead limbs of living trees,
and 4 percent were in living trees.  There was a positive association
between black-capped chickadee use and snag size in snags less than 9
inches (25 cm) dbh [32].  In a riparian area in Colorado with a viable
black-capped chickadee population, snags are not plentiful but large
dead branches are.  In an area dominated by plains cottonwood (Populus
deltoides var. occidentalis) with some peachleaf willow (S.
amygdaloides) and boxelder (Acer negundo), cottonwood snags comprised
2.7 percent of all cottonwood stems.  This density of snags is quite
low, primarily due to the decadence of the stand.  However, limb trees
(trees with more than 3.3 feet [1 m] of dead limbs greater than 4 inches
(10 cm) in diameter) made up 47 percent of the cottonwood population
[27].

In western Montana, McClelland and others [19] observed black-capped
chickadees using cavities excavated by sapsuckers (Sphyrapicus spp.)
[19].  Birdhouses are used occasionally [6].

Roosting:  Black-capped chickadees roost primarily in thick vegetation
or in cavities, particularly on cold nights.  Flocks seldom roost
clumped together, but flock members usually roost near each other [31].

Foraging and Feeding:  Flock members usually feed from 3.3 to 33 feet
(1-10 m) apart, occasionally feeding within 2.5 inches (6 cm) for brief
periods [31].

Breeding Territory:  Black-capped chickadee breeding territory size
varies with habitat quality, black-capped chickadee population density,
rank, and the course of the breeding season [30].  In upstate New York
breeding territories ranged in size from 8.4 acres (3.4 ha) to 17.1
acres (6.9 ha) and averaged 13.2 acres (5.3 ha) [23].  An eastern
Massachusetts population had an average breeding territory size of 10.7
acres (4.3 ha), but ranged from 3.8 to 17.9 acres (1.5-7.2 ha) [30].


FOOD HABITS : 
Foraging:  Black-capped chickadees forage from ground to treetop; ground
foraging birds have usually been displaced by higher ranking birds [30].
Black-capped chickadees forage on tree trunks, branches, and foliage
[11], feeding on insects [34], seeds, and berries.  Five basic foraging
maneuvers used by black-capped chickadees are 1) gleaning (57% of time
spent foraging), 2) hanging from leaf or twig to capture food items
(28%), 3) hovering (8.8%), 4) probing (3.5%), and 5) catching insects in
flight, called hawking (2.4%).  These proportions probably vary with
availability of prey, season, and other factors [31].

Caching:  Black-capped chickadees cache seeds from open cones [11].
Insects are also cached.  Most caching occurs in the fall, but caching
may occur at any time food is plentiful.  Storage sites include bark,
dead leaves, clusters of conifer needles, dirt, and snow.  Black-capped
chickadees scatter-hoard; they hide each individual food item in a
separate spot [31].  Sherry [29] reported that black-capped chickadees
can remember cache sites for at least 24 hours, and Hitchcock and Sherry
[13] reported that captive black-capped chickadees can recover caches
after 28 days.

Animal Foods:  In winter, approximately 50 percent of black-capped
chickadee foods are animal foods, the rest seeds and berries.  During
the breeding season, 80 to 90 percent of the black-capped chickadee diet
is animal foods [18,31].  Winter black-capped chickadee animal foods
consist mostly of eggs of moths, plant lice, katydids, and spiders.  In
summer moths, caterpillars, spiders, beetles (particularly weevils),
flies, wasps, true bugs, plant lice, scale insects, leafhoppers, and
tree hoppers are common food items [18].  Smith [30] described the
black-capped chickadee summer diet as consisting largely of
caterpillars, including some hairy caterpillars such as early instar
gypsy moths and tent caterpillars.  Black-capped chickadees have been
observed taking animal fat from carrion and eating suet and peanut butter
at feeders [30].

Plant Foods:  Black-capped chickadee plant foods are mainly seeds and
berries including goldenrods (Solidago spp.) and staghorn sumac (Rhus
typhina) seeds in fall.  Pine seeds are a main staple in fall, winter,
and spring.  Seeds of hemlocks (Tsuga spp.) and birches are eaten in
winter; seeds or fruits of poison-ivies (Toxicodendron spp.),
blueberries and huckleberries (Vaccinium spp.), bayberries (Myrica
spp.), ragweeds (Ambrosia spp.), sunflowers (Helianthus spp.),
chokecherry (Prunus virginiana), and Virginia creeper (Parthenocissus
quinquefolia) are eaten in spring and summer [18].  Raspberries (Rubus
spp.), cherries (Prunus spp.), and yellow-poplar (Liriodendron
tulipifera) seeds are also consumed [30].

Fluids:  Black-capped chickadees drink when water is available.  Fluids
are derived mostly from foods in winter; highest demand for liquid water
is in summer [31].


PREDATORS : 
Natural predators of the black-capped chickadee include goshawk
(Accipiter gentilis), sharp-shinned hawk (A. striatus), Cooper's hawk
(A. cooperii), American kestrel (Falco sparverius), merlin (F.
columbarius), northern pygmy-owl (Glaucidium gnoma), and northern shrike
(Lanius excubiter).  Around birdfeeders, the black-capped chickadee is
often preyed on by the domestic cat (Felis catus).  Nest predators are
largely excluded by the small size of black-capped chickadee nest
entrance holes, but very small squirrels (Tamiascurius spp.) or
chipmunks (Tamias spp.) occasionally raid black-capped chickadee nests.
Weasels (Mustela spp.) and climbing snakes pose a threat to eggs and
nestlings [30].


MANAGEMENT CONSIDERATIONS : 
A review of Christmas Bird Count data for the Pacific Northwest showed
that most black-capped chickadee populations have apparently been stable
during the past 40 years.  Of 49 locales reporting, 6 showed significant
declines (stations in Alaska, British Columbia, Montana, and Oregon), 5
showed significant increases (British Columbia, California, Montana, and
Washington), and the remaining 38 showed no overall change.  It was
speculated that the "significant" increases and decreases may actually
represent anomalous data [4].

Long-term wildlife management should strive for sites with a mosaic of
age structures [28].  In northwestern Connecticut the clearcutting of 60
acres (24.4 ha) of red pine (Pinus resinosa) within a 321 acre (130 ha)
banding plot had no discernible effect on black-capped chickadee
populations in a long-term population study [17].

Forest clearing can increase edge, which is preferred (but not required)
black-capped chickadee habitat.  Removal of snags and cull trees with
dead limbs decreases available nest sites for black-capped chickadees
[31,32], although black-capped chickadees are listed as tolerant of
habitat alteration [32].

Stauffer and Best [32] listed the following predicted effects of various
types of habitat alteration on black-capped chickadee populations:

removal of all wood vegetation:  elimination
reduce woody vegetation to narrow strips:  negative
woody canopy partly removed:  no effect
woody canopy partly removed, shrubs and saplings thinned:  negative
shrubs and saplings thinned:  negative
snags removed:  negative

Lack of cottonwood regeneration is detrimental to the long-term
stability of cavity-nesting bird populations [17].

In cold-winter areas, feeders often enhance black-capped chickadee
survival, particularly in disturbed areas where food supplies are
limited [31].  Nest boxes can increase available nest sites where
natural cavities are limited.  Nest boxes are not readily used unless
they are half-filled with sawdust, apparently so that the birds have
something to excavate [30].

Black-capped chickadees are only rarely host to the brown-headed cowbird
(Molothrus ater) [31].

Black-capped chickadees are important predators of larch casebearer
larvae and pine sawfly larvae [5].


REFERENCES : 
NO-ENTRY

Related categories for Wildlife Species: Parus atricapillus | Black-Capped Chickadee