The Northern cardinal in the rhododendron outside Pell Murphy's kitchen window in Asheville sang at 07:42 on the twelfth of January in a temperature of 19 degrees Fahrenheit.
This is unusual mostly to people who think of bird song as a spring phenomenon. The cardinal is, in fact, one of the most reliably vocal North American songbirds in winter. He pairs early, holds territory more or less year-round in the southern half of his range, and sings to maintain that territory through the cold months.
Murphy has been keeping a winter-song journal for the cardinals on his quarter-acre suburban lot since November of 2023. The entries are short. Date, time, temperature, weather, which bird, how many phrases.
The journal now runs to three winters. It is the kind of long thin record that produces, eventually, a small useful pattern.
The first pattern is that the cardinals sing more on clear cold mornings than on overcast warm ones. This is contrary to what one might expect. Cold should suppress vocalization in a bird that has to keep its core temperature up.
The bird is, presumably, responding less to the temperature and more to the light. Clear winter mornings have stronger photoperiodic cues, even when they are colder.
The second pattern is the female. The Northern cardinal is one of the few common North American songbirds in which the female sings nearly as much as the male. She has, by Murphy's count, a slightly smaller phrase repertoire, but she uses it.
She often sings from the nest, including during the period of incubation. The male sometimes brings her food and answers her song from a nearby perch. This is the kind of antiphonal behaviour that is more typical of tropical species than of temperate ones.
Murphy's female, whom he calls the Western Hen for the side of the yard she favours, sang on twenty-three of the ninety days he kept the 2025 to 2026 winter journal. The male sang on sixty-one of those days.
The repertoire overlap is high but not complete. The male had four phrase types Murphy never recorded the female using. The female had two phrase types Murphy never recorded the male using.
This is consistent with what published research has found. Female cardinal song is not just a quieter version of male song. It is a related but distinct repertoire.
Susan Smith, at Mount Holyoke, did the careful work on this in the 1970s. She showed that female cardinals sing for territorial purposes much as males do, and that pair members coordinate their song output across the day in patterns that look genuinely communicative.
The literature on female bird song has grown substantially since then. Karan Odom and others have shown that female song is far more widespread, across the songbirds globally, than the old male-centred literature acknowledged.
For the cardinal, the picture is now clear. Both sexes sing. Both maintain territory. Both contribute to the soundscape of a suburban winter morning in North Carolina.
Murphy's journal also shows the seasonal arc. Cardinal song in his yard begins to pick up in late December. It peaks in late February. By April it is folded into the general spring chorus and is no longer notable.
What is notable is that there is song at all in January. Most of the other regular yard birds, the chickadees and titmice and white-throated sparrows, are using call notes through the cold months, not song.
The cardinal is one of the few species where a January walk produces actual song from actual territorial birds. The blue jay sometimes, the Carolina wren often, the white-breasted nuthatch occasionally. But the cardinal is the most reliable.
For the backyard birder, this is a small gift. The species is among the most widely distributed and most easily recognized in eastern North America. The song is loud and patterned and easy to listen to.
And the female, once you start hearing her, is hard to stop hearing. She sings from the holly, from the dogwood, from the top of the bird feeder pole. She has been doing this all along.
Murphy will continue the journal. He hopes to have ten winters of it by the time he retires. The data will go to eBird with location and time, where it joins the long undramatic record that amateurs have been keeping on this species since John James Audubon painted it in 1825.
What it tells us, so far, is mostly the obvious thing said carefully. A common bird in a common backyard is doing more, more often, than most people notice. The cold morning is not the silent one we expect.
