Student or Learner
Carve is cutting and making something, does "carve out" mean actually cutting and shaping something or just making in this case? I think the latter as fish can't cut something.
ex)The stickleback is a small fish that is common in shallow fresh waters. In the spring, each male stickleback carves out a circular nest.....
Not a teacher
About the stickleback
"The males construct a nest from vegetation held together by secretions from their kidneys. The males then attract females to the nest. The female will lay their eggs inside the nest where the male can fertilise them. The male then guards the eggs until they hatch"
Should clarify matters.