[Possible ways of spreading and evolution of alcids]

Based on the published data, a hypothesis is proposed on possible ways of spreading of the Alcids from the center of their primary radiation located in the Pacific. The Alcids colonized the Atlantic first in the Early-Middle Miocene. They rounded North America from the south: at that time, the strait between the Americas was open, while the Bering Strain was closed. Later, in the Late Miocene, Late Pliocene, and Pleistocene, exchange of species between the Atlantic and Pacific took place through the periodically opening Bering Strait.