floating nest
A nest built on water, typically by aquatic birds such as grebes, using aquatic plants.
カイツブリは浮き巣を作ることで知られている。
The little grebe is known for building floating nests.
Standard kanji spelling.
Variant spelling without okurigana.
Compound of 浮き (uki, 'floating') + 巣 (su, 'nest').