Filyos Delta is an important delta located between the Kızılırmak Delta and Sakarya River in the Western Black Sea Region. Deltas formed in areas where rivers join the sea are places where biological diversity and consequently bird diversity are the highest.

Zonguldak is among 10 provinces in Turkey in terms of species diversity. 20 of the 30 bird species that are rare in the country are seen in the Filyos Delta. Filyos Delta is a rich environment not only for birds but also for many living groups. The natural structure (morphology) and resources are a very rich delta in terms of biodiversity. The wetland is the resting and feeding area for many bird species, and there are many such as shorebirds, herons, reeds and songbirds in the reeds.a