bird — the oddly named process that syncs your iCloud Drive

Last updated: 2026-07-30

What it is

bird is the sync engine behind iCloud Drive. The name is an abbreviation of the internal CloudDocs daemon and was never meant to be read by users, which is why it is one of the most searched-for process names on macOS: it appears near the top of Activity Monitor, moves a great deal of data, and tells you absolutely nothing about itself.

Its scope is wider than many people expect. Beyond the iCloud Drive folder itself, it also handles the Desktop & Documents sync option, which places two of the most-used folders on the Mac under iCloud management. If that option is on, bird is syncing a large part of your working files.

Why it talks to the network

It uploads what you add and downloads what arrives from elsewhere. Three situations account for nearly all of the surprising volume.

Initial sync. Turning on iCloud Drive, or enabling Desktop & Documents for the first time, means everything already in those folders has to be uploaded. On a Mac with years of accumulated files this is a large, one-time transfer that can run for hours.

A new device. Signing in on a new Mac reverses the direction — files come down rather than going up. Optimised storage means this is often partial rather than complete, but it is still substantial.

Ordinary work. Saving a document, moving a folder in, an app writing to its iCloud container. These are proportional to what you did and generally unremarkable.

How much traffic is normal

Entirely determined by what is in the folder, which makes bird unusual: for most system processes a large number is suspicious, but for this one it is often simply arithmetic.

Routine editing produces modest traffic — a document saved is a document uploaded. Initial sync of a well-used Desktop and Documents folder can easily reach tens of gigabytes, and that is correct behaviour rather than a fault.

The pattern worth investigating is sustained activity with an empty explanation: bird transferring continuously for days when you have not added anything and the sync should long since have finished. That usually means a file it cannot reconcile, and it will keep retrying indefinitely.

Can you turn it off

Not by stopping the process, and the real switch has consequences. bird is a throttleOK process.

Killing it achieves nothing — launchd restarts it and the queued sync resumes. The genuine control is in System Settings › your Apple Account › iCloud › iCloud Drive, where you can disable Desktop & Documents sync or iCloud Drive altogether.

Be careful with that switch. Turning off Desktop & Documents sync changes where those files live, and macOS will ask you to choose whether to keep local copies. This is a data-management decision, not a bandwidth setting, and it deserves more thought than a network toggle.

When the problem is timing rather than the sync itself, throttle instead. A large upload that finishes overnight instead of in the next hour is still doing its job, and file sync is specifically built to survive slow and interrupted connections.

Seeing what it actually used

bird is the process where "is this normal?" depends entirely on context that a live meter cannot show. Forty gigabytes the week you enabled Desktop sync is expected; forty gigabytes every week is not.

Bytetally records per-process upload and download over time, so you can tell an initial sync from a stuck one by looking at whether the volume ever tapers off. And when a sync genuinely does need to yield to something more urgent, capping its rate keeps your files moving while giving the bandwidth back to whatever is in front of you.

Related processes

Common questions