(Poecile rufescens)
Year-round
HABITAT: Prefers shade and cover of dense, wet, coniferous forest along Pacific coast; some mixed woodlands in California
DESCRIPTION: Dark-brown cap, white cheek, blackish-brown bib; white breast and grayish-white below; rich chestnut on back and sides (though sides are paler in southern part of range)
What a handsome creature, yet what a puzzle, as this chickadee has lost its whistle. Other common chickadees, including the Black-capped, Carolina, and Mountain Chickadees, have a whistled song, and males of these species sing their whistles throughout the dawn chorus (an unpaired male, too, whistles all day long to attract a mate). But Chestnut-backed Chickadees are more similar to the closely related Mexican Chickadees to the south and Boreal Chickadees to the north—three species in which the distinction between their songs and calls is not so clear.
The other vocalizations of this chickadee are much like those of other chickadee species, except higher-pitched overall, given that this is the smallest of the chickadees. They have the typical aggressive “gargle,” sounding much like a jumble of short click notes, but it seems to be rarely used. The chick-a-dee-dee call is high, thin, and scratchy, more of a tsick-i-see-see, and it’s by far the most common call heard from these Chestnut-backs. Their chick-a-dee-dee call seems especially complex and variable when compared to that of other chickadees, too, as if it has extra importance in their communications.
So what does a male Chestnut-back do for a song? On occasion, especially in early spring, he seems to use a relatively simple form of a gargle call as a song, sometimes repeating a given note several times, much like a Chipping Sparrow song. For a dawn song, he rises to the treetops (or sometimes perches near the nest) and “sings” his chick-a-dee-dee “call.” It’s puzzling, intriguing, and makes us think twice about how we classify the sounds of birds as either calls or songs.
Tsick-i-see-see calls Simple gargle calls 
