Vertebrate Zoology - V. M. Konstantinov 2011

Chordates
Terrestrial, or Tetrapod, Vertebrates — Vertebrates with Embryonic Membranes
Class Birds — Subclass Fan-tailed Birds, or True Birds — Superorder Neognathae, or Typical Birds — Order Pelecaniformes, or Totipalmates

The order comprises 6 families and 60 species. These are large (body mass 7 — 14 kg) freshwater and partly marine birds with very short legs, where all four toes are connected by a broad web, and the hallux is directed inwards rather than backwards. The bill is long, always featuring a more or less extensible bare gular pouch between the rami of the lower Mandible. Monogamous. The clutch contains 1 — 6 eggs, incubated by both parents for 5 — 6 weeks. The chicks hatch helpless and are fed by both parents for 6 — 15 weeks. Distributed worldwide, excluding polar regions.

The pelican family (Pelecanidae) includes very large birds with a massive, flattened bill, between the lower rami of which lies a large, highly extensible gular pouch. The upper mandible terminates in a downward-curved hook. The body is bulky, the neck long and relatively slender; the legs and tail are short and broad (see Fig. 145).

Two species are found in Russia: the great white pelican (Pelecanus onocrotalus) and the Dalmatian pelican (P. crispus). They are large in size, particularly the white pelican, with a mass of up to 12 kg. The plumage of adult birds is white, with a pinkish hue in the great white pelican. They inhabit hot and warm zones along the shores of the Black, Caspian, and Aral Seas, as well as major rivers and lakes in the Caucasus and Central Asia. They nest in colonies on lakes and river channels overgrown with reeds, building nests from plant material and silt. The clutch contains 1 — 6 eggs. Both parents incubate for 30 — 40 days. The chicks are fed for 2 months or more.

Pelicans are exceptional swimmers, but they cannot dive. They feed on fish caught in shallow waters. Occasionally, when fishing, the birds form a line and swim toward the shore while making a loud commotion by beating the Water with their powerful wings, driving the fish ahead of them so that they concentrate near the bank and become easy prey. Cormorants frequently join pelicans in these cooperative feeding sessions, diving into the water and flushing the fish from below.

The cormorant family (Phalacrocoracidae, see Fig. 145) comprises medium and small-sized birds with a more slender build than pelicans and legs set far back. A perched bird holds its body almost vertically, supported by a long tail made of stiff feathers. The bill is cylindrical, ending in a large hook. The gular pouch is poorly developed. Among the species found in Russia, the great cormorant (Phalacrocorax carbo) is the most common. It nests in colonies along sea coasts, in the lower reaches of major rivers, and on large lakes. Cormorants build their nests in reeds, on trees, or on cliffs, but always in close proximity to water. The clutch contains 2 — 6 pale blue or greenish eggs. Incubation lasts 7 — 8 weeks. Both parents participate in caring for the chicks, feeding them in a highly unusual manner: the adult birds open their mouths wide, and the chicks thrust their heads deep inside to retrieve semi-digested fish from the parent's highly extensible Esophagus. Much like pelicans, cormorants often hunt fish by forming a large semicircle and swimming toward the shore while noisily beating their wings on the water and gradually narrowing the formation. However, unlike pelicans, cormorants also hunt fish underwater, proving to be excellent divers.