Perch on (something) phrasal verb
To cause something or someone to maintain a balanced standing or sitting position or a ready posture.
She perched her son on the baby booster seat while she prepared dinner.
Peter was perched on the bicycle. He found it difficult to learn to ride a bike.
To take a seat and relax
Used to say that someone is not working or producing anything
To put, throw, drop, someone, something, or oneself down heavily and without taking care.
The verb "perch" should be conjugated according to its tense.
The white bird has perched on this fence for several minutes.
Many sources point to the 1520s for the origin of this phrase.
It was often said by a photographer when he would like small children to look at the camera and smile before he took a photo.
When the photographer said “watch the birdie”, all of us looked at the camera and smiled.