Where to Find and Catch Trumbeak
From Pokemon Go Wiki
Trumbeak are found and captured in Nest and Habitat locations.
Nests
Trumbeak Nests are locations that consistently spawn Trumbeak.
Habitats
Trumbeak Habitats are spawn locations where Trumbeak is likely to be encountered, but not guaranteed the way a Nest is.
Additional Tips and Information
Best Nests
If you know a really good nest or any of the nests above is really good, list them here: