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Fall 2012

Urban Jungle

The changing natural world at our doorsteps | Illustration and text by Patterson Clark      

Northern Mockingbird, Mimus polyglottos

Mimus polyglottos

October 23, 2012

Fall mockingbird songs

Mild days, chilly nights, mockingbird songs: Sounds like springtime, but it's only a dress rehearsal.

In October, young northern mockingbirds are carving out their territories and stepping up to debut their songs.

Most of the prominent warbling is performed by single males trying to attract a mate. Females also sing, softly and less frequently, and sometimes establish fall territories of their own without a mate. But it may be more advantageous to pair up in the fall, giving those birds a head start on breeding once spring arrives.

Mockingbirds' autumn song will subside in November, but singing returns in late winter with a repertoire distinctly different from fall's collection. Although singing may help advertise a bird's territory, song is probably most effective at stimulating nesting and other aspects of reproduction and pair bonding.

Male mockingbirds even sing quietly while mating. Females rarely sing during breeding season — and only when the male is away from the territory.

Mockingbirds can master as many as 200 calls, and they continue to learn new ones as they age, inspired by other bird species, insects, mammals, machines, car alarms, cellphones, toy horns — even neighboring mockingbirds.

But once the chicks arrive, singing is shelved. Mockingbirds that raise the most young tend to sing the least while parenting. But singing starts up again between each of the summer's several broods — or if the mate disappears.

That middle-of-the-night mockingbird serenade that you hear during a full moon in the spring and summer almost always emanates from a male without a mate. He is perhaps using the relative quiet of night to make his song stand out. A single female hearing his personal ad can perhaps the next day pick his voice out of a crowd of performing mockingbirds.

But no mockingbird flits around flirting with a potential mate at night. There are too many cats and screech owls on the prowl. That sleepless single male may be risking his neck with a gutsy nocturnal spectacle, but more likely than not he is perched in a very protected spot.

Sources: The Birds of North America: Life Histories for the 21st Century, The Auk, Journal of Field Ornithology