macOS iCloud Drive Sync Engine Container & Cache (bird)

Bottom Line: It is safe to clear com.apple.bird cache if iCloud Drive syncing is stuck or consuming excessive storage space. bird is the core macOS daemon responsible for syncing files between your Mac and Apple iCloud servers.

Why Does macOS bird Cache Exist?

The bird process monitors local iCloud Drive folders (~/Library/Mobile Documents) and manages file downloading, uploading, and conflict resolution.

• Primary Purpose: Staging ground for pending iCloud file downloads and sync manifests.
• Storage Growth: Interrupted file downloads or syncing large video projects expand com.apple.bird cache to 3 GB to 25 GB+.
• Location: Stored in ~/Library/Caches/com.apple.bird.

What Happens If You Clear bird Cache?

• System Safety: ✅ Safe to Clear. Local files saved inside iCloud Drive remain untouched.
• Sync Reset: macOS restarts the bird daemon and reconciles file manifests with iCloud servers cleanly.
• Reclaimed Storage: Reclaims 3 GB to 25 GB+ of storage space.

How to Clear macOS bird Cache

# Kill bird process and clear cache container
killall bird
rm -rf ~/Library/Caches/com.apple.bird/*

Frequently Asked Questions (FAQ)

Why is bird taking up high CPU and network bandwidth?

bird spikes CPU when downloading large desktop files or syncing desktop folders after toggling “Desktop & Documents Folders” in iCloud settings.