Ground - nesting birds which rely on crypsis for concealment have nests made from local materials which blend in with the background , the eggs and young too are cryptic ; .
Birds which do not use crypsis for hiding their nests may not have cryptic eggs or young .
Ground - nesting birds which rely on crypsis for concealment have nests made from local materials which blend in with the background , the eggs and young too are cryptic ; whereas birds which do not use crypsis for hiding their nests may not have cryptic eggs or young .