Aquatic bird and Swamphen

Aquatic bird noun - Wading and swimming and diving birds of either fresh or salt water.

Swamphen and aquatic bird are semantically related. In some cases you can replace term "Swamphen" with "Aquatic bird", this terms are similar.

Swamphen noun - Any of various small aquatic birds of the genus Gallinula distinguished from rails by a frontal shield and a resemblance to domestic hens.

Aquatic bird and swamphen are semantically related. You can use "Aquatic bird" instead a noun "Swamphen".