Recognise grief for what it is
Bonded birds eat, sleep, preen, and call together for years, sometimes decades, so the survivor's behaviour after a companion dies is grief, not naughtiness or simple loneliness. Expect the patterns owners report again and again: calling repeatedly for the missing bird, searching the cage and the room, going quiet and withdrawn, eating less, or clinging to people it previously ignored. An older bird may also lose condition quietly, because appetite and sleep are fragile at its age. Your first job is simply to take the change seriously and keep the bird's world steady while it works through the absence — the survivor has lost its flock, its mirror, and its daily partner in one blow.
Hold the routine, and become more present yourself
Do not rearrange the cage, move it to a new room, or change feeding and cover times in the weeks after the loss; routine is the survivor's anchor when its social world has collapsed. Spend more time near the cage yourself — working, reading, eating where the bird can see and hear you — and talk to it through the day, because a bonded bird is used to near-constant company and your presence partly fills the silence. Offer favourite foods by hand, introduce one gentle novelty at a time, such as a new chew toy or a foraging treat in a familiar cup, and keep out-of-cage time calm and close. If the dead bird's body is available and the vet agrees it is safe, some owners let the survivor see it briefly; many birds settle faster after seeing than after a companion simply vanishes.
Watch the body while you tend the heart
Grief becomes a veterinary matter when the survivor stops eating properly, loses weight you can feel in the keel, produces persistently scant droppings, or stays fluffed, sleepy, and uninterested beyond the first days. Older birds have small reserves, so weigh the bird weekly on a kitchen scale if it tolerates it, note what it actually eats rather than what is offered, and call an avian vet promptly if eating does not pick up — a vet can rule out the possibility that whatever took the companion is also affecting this bird, which matters especially if the death was sudden or unexplained. Keep notes of appetite, weight, and behaviour; a trend you can show the vet is worth far more than a worried summary.
A new companion is a later question, answered by the bird
Resist replacing the companion immediately, however hard the calling is to hear. A new bird introduced to a grieving, older resident can be rejected, bullied, or simply be one change too many, and it deserves its own careful quarantine and introduction regardless. Months later, if your bird is eating, playing, and engaging again but still clearly pines for company, a carefully matched companion — often another older bird — can be introduced slowly, in separate cages side by side, letting the survivor choose the pace. Meanwhile, the bird that died deserves remembering in its own right, not erasing. KinsLe's Memorial Accounts hold that companion's photos and story in a free memorial profile, so the pair's long history stays together while you give the survivor the time it needs.