quail
鴳 centers on the quail, a small ground bird. The meaning is specific to this bird species.
鴳 combines 安 (likely phonetic) with 鳥 (bird), forming a character for a type of bird, specifically the quail.
A bird (鳥) that is safe and calm (安) like a quail hiding in the grass.
For アン, imagine a quail named Ann: Ann -> アン, a small bird resting quietly.