What Is bird on a Mac? iCloud Drive and High CPU

Activity Monitor shows a process called bird, sometimes next to one called cloudd, using CPU or network while you are not doing anything in particular. The name gives nothing away.

The short answer: bird is the macOS process behind iCloud Drive, and cloudd is the one behind CloudKit, the service many Apple and third-party apps use to sync their data through iCloud. Both get busy when there is a lot to sync, such as a large folder added to iCloud Drive or a new Mac downloading your files. They are safe, they settle when syncing is done, and quitting them does not stop the sync.

What bird does

Apple's manual page describes bird as "one of the system daemons backing the Documents in the Cloud feature", and it runs from Apple's iCloudDriveCore framework. In practice it is the process that keeps the files in your iCloud Drive in step between your Mac and iCloud, uploading what you change and downloading what changed elsewhere.

On our test Mac, running macOS 27.0.1, bird ran under the logged-in user's account from the system iCloudDriveCore framework.

What cloudd does

Its manual page calls cloudd "the system daemon backing the CloudKit feature." CloudKit is how apps store and sync their own data in iCloud. On our test Mac there were two copies, one under the user's account and one under root, both from the system CloudKitDaemon framework.

Why bird and cloudd use CPU and network

They work hardest when a lot has to move:

• A large folder added to iCloud Drive, which has to upload.
• A new Mac or a fresh sign-in, when your iCloud Drive contents download.
• Files changing constantly inside iCloud Drive, for example a project folder that an app rewrites often.
• Apps syncing a lot of data through CloudKit, which shows up as cloudd.

The transfers themselves often appear under nsurlsessiond, the macOS service that carries background downloads and uploads. Our guide to nsurlsessiond shows how to see which apps have been using it.

How to check whether iCloud Drive is still syncing

macOS includes a command-line tool for iCloud Drive, brctl, whose manual page describes it as the tool to "manage the CloudDocs daemon." For a status summary, run:

brctl status

It lists your iCloud Drive containers and whether each has caught up with the server. On our test Mac it reported the container as caught-up, with the time of the last sync. Until it has synced, it will not say caught up. If the output opens in a scrolling view, press q to get back to the prompt.

Are bird and cloudd safe?

Yes. Both are part of macOS. You can check their paths and the account they run under in Terminal:

ps -axo user,pid,pcpu,comm | grep -E "/(bird|cloudd)$"

bird should run from inside iCloudDriveCore.framework and cloudd from inside CloudKitDaemon.framework, both under /System/Library/PrivateFrameworks. A process with either name running from anywhere else would be worth investigating.

How to calm them down

• Let the sync finish. Leave the Mac on, online and plugged in after adding a large folder or setting up a new Mac. brctl status tells you when iCloud Drive has caught up.
• Find the files it is working on. bird runs under your account, so Activity Monitor can show its open files: double-click bird, then open the Open Files and Ports tab. A folder that keeps appearing is the one keeping it busy.
• Keep busy working folders out of iCloud Drive. Folders that an app rewrites all the time, such as build output or a virtual machine image, keep bird working constantly. Move them somewhere outside iCloud Drive.
• Do not bother quitting them. When we quit bird on macOS 27, it exited cleanly and macOS started a new copy 11 seconds later, and the syncing carried on.

See it in your menu bar

bird and the user copy of cloudd run under your own account, so MacStats can see them. When either is busy, it appears in MacStats' Top CPU or Top RAM list, and with MacStats Pro, clicking it gives you a plain-English explanation of what it is doing and whether you need to act. MacStats' menu bar also shows your Mac's live upload and download speed, so a big iCloud transfer is obvious the moment it starts.

See what iCloud is doing before the fans tell you.

Download MacStats for Free

Frequently asked questions

What is bird on a Mac?

It is the macOS process behind iCloud Drive. Apple's manual page describes it as one of the system daemons backing Documents in the Cloud, and it runs from the system iCloudDriveCore framework.

What is cloudd on a Mac?

It is the system daemon behind CloudKit, the service apps use to store and sync their data in iCloud.

Why is bird using so much CPU?

Because iCloud Drive has a lot to sync, for example a large folder you just added, a new Mac downloading your files, or files inside iCloud Drive that change constantly. It settles when syncing is done.

How do I check if iCloud Drive is still syncing on a Mac?

Run brctl status in Terminal. It lists your iCloud Drive containers and shows whether each has caught up with the server.

Can I quit bird?

You can, but it does not help. In our test on macOS 27, macOS started a new copy 11 seconds later and syncing carried on. Let the sync finish instead.