Help · Is it safe to delete?
What are bird and Mobile Documents?
bird is one of the macOS processes behind iCloud Drive. ~/Library/Mobile Documents is where iCloud Drive keeps its files on your Mac.
Safe to delete? Not in Finder. Deleting or moving files out of iCloud Drive removes them from iCloud Drive on all your devices, Apple warns.
Free the space safely
- In Finder, Control-click a file or folder in iCloud Drive and choose Remove Download. It stays in iCloud, but no longer takes space on this Mac.
- Or turn on Optimise Mac Storage in iCloud Drive settings, so macOS removes local copies when space is low.
The bird manual page says it shouldn't be run by hand. If it's busy, it's usually syncing. More: iCloud Drive taking up space.
Sources: macOS bird manual page; Apple Support, iCloud Drive on Mac (macOS 27); Eclectic Light Company, 25 Aug 2026. Checked October 2026.
Find out what's safe to remove.
Pangalin Space Manager's free scan shows what's using your disk, folder by folder, and labels each item: safe to clean, can move, or needs review. macOS's own files are marked so you don't delete what your Mac needs.
Free to scan · first 5 GB freed free · Notarised by Apple · Apple silicon, macOS 13 or later