The cooing sounds like a bird who cannot sleep. In his own frame of reference, though, he is not awake at the wrong time at all. He is a bird who has watched the light come up, and he is doing exactly what a dove does when the day starts.
Doves take their schedule from light more than from clocks. A full moon shining through a thin curtain, or a streetlight that switches the whole window to a pale glow, can cross the brightness line a dove reads as dawn. His body responds the way it is built to respond: wake, stretch, and coo, because cooing at first light is how a male dove announces himself, holds his territory, and calls to his mate or flock. He will repeat it as long as the false dawn lasts outside the glass.
Cooing Is a Daytime Signal, Not Distress
It helps to separate the sound from the worry it causes at 3 a.m. Cooing is ordinary dove communication, used in daylight for greeting, courtship, and contact, and a bird cooing at a bright window at night is using the same healthy signal at the wrong hour. He is not crying, not calling for rescue, and not necessarily even unhappy. He is misinformed by the light.
That distinction changes the fix. A distressed bird would need company, comfort, or a vet. A dove fooled by moonlight needs the information corrected: the night has to become dark enough that his body stops reading it as morning. Responding to every night coo with visits, talking, and lights switched on teaches a second problem on top of the first, because now the cooing also summons his favorite people. Quiet, darkness, and patience are the whole treatment for the signal itself.
Making the Night Truly Dark
Cover the cage with a blackout cover that wraps fully and blocks light on every side, or move the cage's night position away from the window the streetlight hits. If the cage stays by the window, blackout curtains drawn completely are the alternative, and a combination of curtains plus cover is fair when the streetlight is strong. Check the result from the bird's position after dark: if you can still see the pale shape of the window from the perch, he can too, and the fix is not finished.
Keep the dark hours consistent as well as dark. Doves settle best when lights-out and morning arrive at roughly the same times daily, so the body stops scanning the night for a dawn that keeps moving. Let morning come properly when it comes: uncover the cage, let real daylight in, and greet him then. That sharp contrast, true dark followed by true light, is what retrains the pattern, and many doves quiet down within days once the contrast is restored. A cover that breathes well and fits without gaps at the top does the job better than a thin sheet thrown over one side.
When Night Cooing Is Worth a Second Look
Light explains cooing that tracks bright nights: full moons, clear skies, the weeks after a new streetlight appears. Cooing that continues in complete darkness, or that arrives alongside other changes, deserves a fresh look at the whole bird. Check that he is eating during the day, that his droppings look normal for him, and that he is active and bright in the morning rather than fluffed and quiet.
A dove who coos at night and is also off his food, losing weight, or breathing with effort is showing a different picture, and that combination goes to a vet rather than to more curtain adjustments. The same applies if a new cage mate, a moved cage, or building work has changed his nights at the same time as the cooing began, because then the light may be only part of the story. For the ordinary moonlight case, the cover routine is the answer, and in KinsLe the household can keep it from slipping, since Care Teams lets whoever closes up the house mark the cover done for this dove each evening.