IPA: //ˈeɪviˌærɪst//
KK: /ˈeɪviˌærɪst/
A person who takes care of birds in a large enclosure called an aviary.
The aviarist spent hours observing the different species of birds in his aviary.
Aviarist is formed from "aviary" (from Latin "aviarium", meaning a place for birds) and "-ist" (meaning one who practices or is concerned with). An aviarist is someone who is involved with or specializes in the care and breeding of birds, particularly in an aviary setting.
Think of an 'aviary' where birds are kept, and remember that an 'aviarist' is someone who specializes in caring for birds.