Pursuit diving is the means of acquiring food for most of the marine swimming birds. Propulsion underwater can be obtained by wings or feet but wing-propelled divers are generally faster than foot-propelled divers.

In both cases, the use of wings or feet for diving has limited their utility in the appendage primary endeavors, whether flying or walking.

The birds in the family of Alcidae are commonly called auks or alcid. These birds are pelagic swimmers and are notable for their ability to fly under water as well as in the air. However, when they come to land, their walking appears clumsy.

Several species have different common names in Europe and North America. The guillemots of Europe are referred to as murres in North America, if they occur in both continents, and the little auk is referred to as the dovekie.

Alcids are superficially similar to penguins having black-and-white colors, upright posture and some of their habits despite not being closely related to penguins.

Alcids are monomorphic, which means that the males and females are similar in appearance.

010ra Razorbill Alca torda, L 17 inches

010do Dovekie Alle alle, L 8 inches

012ma Marbled Murrelet Brachyramphus mormoratus, L 10 inches

012rh Rhinoceros Auklet Cerohinca monocerata, L 15 inches

011bl Black Guillemot Cepphus grylle, L 13 inches

011pi Pigeon Guillemot Cepphus columba, L 13 inches

011at Atlantic Puffin Fratercula arctica, L 12 inches

011tu Tufted Puffin Fratercula cirrhata, L 15 inches

164ho Horned Puffin Fratercula corniculata L 15 inches (Arctic only)

012ca Cassin′s Auklet Ptychoramphus aleuticus, L 9 inches

012an Ancient Murrelet Synthliboramphus antiquus, L 10 inches

012cr Craveri′s Murrelet Synthiboramphus craveri, L 10 inches

012xa Xantus′ Murrelet Synthiboramphus hypoleucus, L 10 inches

010co Common Murre Uria aalge, L 18 inches

010th Thick-billed Murre Uria lomvia, L 18 inches

A phalarope is any of three living species of slender-necked shore birds in the genus Phalaropus of the bird family Scolopacidae.

The English and genus names come through French phalarope and scientific Latin phalaropus from Ancient Greek phalaris, coot, and pous, foot. Coots and phalaropes both have lobed toes.

The sexual dimorphism and contribution to parenting are reversed in the three phalarope species. Females are larger and more brightly colored than males. The females pursue and fight over males, then defend them from other females until the male begins incubation of the clutch.

Males perform all incubation and chick care, while the female attempts to find another male to mate with. If a male loses his eggs to predation, he will often rejoin his original mate or a new female, who will lay another clutch.

Once it becomes too late in the season to start new nests, females begin their southward migration, leaving the males to incubate eggs and care for the young.

Phalaropes are uncommon among birds and vertebrates in general in that they engage in polyandry, one female taking multiple male mates while males mate with only one female. Specifically, phalaropes engage in serial polyandry, wherein females pair with multiple males at different times in the breeding season.

013re Red Phalarope Phalaropus fulicaria, L 8 1/2 inches

013rn Red-necked Phalarope Phalaropus lobatus, L 7 1/2 inches