Bubo bubo
Krumovitsa River Valley is one of the most important areas in Bulgaria for breeding black storks ("Ciconia nigra") and Egyptian vultures ("Neophron percnopterus"). Other nationally significant populations breeding at site are the short-toed snake eagle ("Circaetus gallicus") (1 pair), Eurasian eagle-owl ("Bubo bubo") (1–2 pairs) and the olive-tree warbler ("Hippolais olivetorum") (2–5 pairs).