Ingo Arndt / White Stork (Ciconia ciconia) parent with chicks on nest, Danube Delta, Romania

Ingo Arndt / White Stork (Ciconia ciconia) pair courting at nest, Danube Delta, Romania

Ingo Arndt / Squacco Heron (Ardeola ralloides) wading in wetland, Danube Delta, Romania

Ingo Arndt / Great White Pelican (Pelecanus onocrotalus) flock in wetland, Danube Delta, Romania

Ingo Arndt / Black-headed Gull (Chroicocephalus ridibundus) flying and calling, Danube Delta, Romania

Ingo Arndt / Black-headed Gull (Chroicocephalus ridibundus) flying, Danube Delta, Romania

Ingo Arndt / Black-headed Gull (Chroicocephalus ridibundus) flying and calling, Danube Delta, Romania

Ingo Arndt / Eared Grebe (Podiceps nigricollis) swimming, Danube Delta, Romania

Ingo Arndt / Tisza Mayfly (Palingenia longicauda) swarming, Danube Delta, Romania

Ingo Arndt / Common Tern (Sterna hirundo) flying and calling, Danube Delta, Romania

Ingo Arndt / Great Cormorant (phalacrocorax carbo) flying, Danube Delta, Romania

Ingo Arndt / Great Cormorant (phalacrocorax carbo) flying, Danube Delta, Romania

Ingo Arndt / Great White Pelican (Pelecanus onocrotalus) flying, Danube Delta, Romania

Ingo Arndt / Black-headed Gull (Chroicocephalus ridibundus) flying and calling, Danube Delta, Romania

Ingo Arndt / Black-headed Gull (Chroicocephalus ridibundus) flying and calling, Danube Delta, Romania

Ingo Arndt / Great White Pelican (Pelecanus onocrotalus) flying, Danube Delta, Romania

Ingo Arndt / Whiskered Tern (Chlidonias hybrida) male passing mayfly to female during courtship, Danube Delta, Romania

Ingo Arndt / Whiskered Tern (Chlidonias hybrida) pair mating on newly built nest, Danube Delta, Romania

Ingo Arndt / Whiskered Tern (Chlidonias hybrida) flying and calling, Danube Delta, Romania

Ingo Arndt / Whiskered Tern (Chlidonias hybrida) pair mating on newly built nest, Danube Delta, Romania

Ingo Arndt / Whiskered Tern (Chlidonias hybrida) male passing dragonfly to female during courtship, Danube Delta, Romania

Ingo Arndt / Whiskered Tern (Chlidonias hybrida) pair courting on newly built nest, Danube Delta, Romania

Ingo Arndt / Whiskered Tern (Chlidonias hybrida) calling on newly built nest, Danube Delta, Romania

Ingo Arndt / Great White Pelican (Pelecanus onocrotalus) taking flight, Danube Delta, Romania

Ingo Arndt / Great White Pelican (Pelecanus onocrotalus) flock flying, Danube Delta, Romania

Ingo Arndt / White Stork (Ciconia ciconia) parents with chicks on nest, Danube Delta, Romania

Ingo Arndt / White Stork (Ciconia ciconia) pair displaying at nest with chicks, Danube Delta, Romania

Ingo Arndt / Great White Pelican (Pelecanus onocrotalus) flock, Danube Delta, Romania

Ingo Arndt / White Stork (Ciconia ciconia) parent preening with chick in nest, Danube Delta, Romania

Ralph Martin/ BIA / Wood Lark (Lullula arborea), Romania

Ralph Martin/ BIA / Savi's Warbler (Locustella luscinioides), Romania

Oscar Diez/ BIA / Great Black-headed Gull (Ichthyaetus ichthyaetus) flying, Romania

Oscar Diez/ BIA / Grey-headed Woodpecker (Picus canus) male, Romania

Oscar Diez/ BIA / Dalmatian Pelican (Pelecanus crispus) pair, Romania

Oscar Diez/ BIA / Dalmatian Pelican (Pelecanus crispus) group, Romania

Oscar Diez/ BIA / Dalmatian Pelican (Pelecanus crispus) flying, Romania

Oscar Diez/ BIA / Dalmatian Pelican (Pelecanus crispus) flying, Romania

Oscar Diez/ BIA / Dalmatian Pelican (Pelecanus crispus) group, Romania

Oscar Diez/ BIA / Hooded Crow (Corvus cornix), Romania