Species: The Mountain Chickadee, or MOCH, is closely related to the Black-capped Chickadee (Poecile atricapilla), may hybridize. Pair bonds may last for life.
Interesting Facts: MOCHs cache conifer seeds. May wipe bill after handling food like suet. May engage in Snake Display on nest.
Identification: Black cap on head with white eyebrow and black stripe over eye, chin and throat are black, cheeks are whitish, wings and tail gray with some olive/tan hues, breast and belly grayish white, bill black, legs and toes blue-gray. Sexes look alike although males are a bit bigger and have longer wings. Juveniles look like adults but are smaller.
Distribution: Southern Arizona, Baja California north to British Columbia and Yukon Territory (BNA). West and central Montana and west Texas? (Western Bird's Nests) May "irrupt" (move to another area) if food is scarce, or in the fall after breeding.
Preferred Nesting Habitat: Montane coniferous forest, especially with pine, spruce-fur and piñon-juniper with sparse tree canopy and open understory.
Nesting Behavior: Breeding territory about 6.5 hectares. May give Snake Display when object (like a mirror) is inserted into cavity or when a human approaches. Will not return to a failed nest site, but may re-use successful sites in subsequent years. Female roosts in nest cavity from building nest until nestlings are fully feathered. Sometimes sits on rim of nest. Tremble-thrusting occurs.
Nestboxes: Seldom picks cavities with entrances much larger than body diameter. Sometimes roosts in boxes or old nests. Will nest in rotten stubs but prefers hard-walled cavities. Will use wooden, sawdust and concrete nestboxes.
Nestbox Location: No preference for compass direction of entrance. May prefer boxes over natural cavities. For natural cavities, use ones that are high (e.g., 4.82-15.6 meters [BNA], 18 inches-80 feet [Western Bird's Nests) in large trees. Typically 6-15 feet high (Western Bird's nests); 4-10 feet high (Mountain Bluebird), may prefer high boxes.
Recommended distance between nestboxes:
Monitoring: Unincubated eggs usually covered with a fur plug. which makes counting difficult (do not touch eggs as they may be very fragile.) When monitor approaches box, adult outside may give loud Chick-a-Dee-Dee-Dee call, and do snake display on nest. Weekly monitoring after hatching is usually okay. Young may prematurely fledge on or after day 13 if disturbed.
Nesting Timetable (typical):
Excavation or nest site selection: Pairs form in September. Uses pre-existing cavities. Female selects site.
Nest construction: Begins less than 1 week before laying. Circular base of rotten wood chips or lichen, moss, grass, with loose fur (from mammal scat, owl pellets etc.) or plant down on top, then a distinct cup molded in fur and plugged with looser fur. Nest additions continue after laying.
Egg laying: April - June, depending on location. Older females lay earlier. In cold temperatures, early clutches may fail to hatch, maybe because female is away from the nest while looking for food. Nestboxes and extra food may result in earlier laying. Typically lay one egg per day, 7-9 eggs (sets of 10-12 have been seen - result of egg dumping? Birder's Handbook says 5-9). Unincubated eggs usually covered with a fur plug. Only female incubates. Eggs are ovate to rounded-ovate, some unmarked pure, dead white to entirely marked with tiny reddish-brown dots which may be concentrated on the large end, smooth shells, little or no gloss.
Incubation: 12-15 days, depending on weather.
Hatching: Hatchlings peep faintly the day they hatch. Adults remove eggshells after hatching. The nestlings have tufts of natal down on their head and spine, and their eyes are closed. Rictal flanges are yellow.
Development: Nestlings are fed whole arthropods. By day 2 they can lift their heads, they beg in response to sound by day 3 and open their eyes on day 6. Fully feathered at 10-11 days. Males may bring in nest material while nestlings are present. Parents remove fecal sacs. Older nestlings may wing quiver while begging. Male sometimes broods young while female is out. May faintly call (fee-bee, chick-a-dee) when approaching the nest with food. Each nestling is fed 15-45 times a day, depending on age. Excrement may accumulate in the nest 1-2 days before fledging.
Fledging: 18-21 days (longer than Black-capped Chickadee). They can fly about 25 m at first, after 2-3 days they can fly more strongly.
Dispersal: Fledglings stay with parents for 2-3 weeks. Dispersal 30 days after fledging, all disperse in first summer.
Number of broods: Second brood may occur after cold, wet weather during an early first brood.
The chickadee is a voluble little bird; when two or more are together they are full of conversation, exchanging bright, cheery remarks back and forth.
- Windsor Marrett Tylor, Life Histories of Familiar North American Birds, Black-capped Chickadee, 1947
