The strength of migratory connectivity is a continuum that ranges from weak to strong. When all individuals from a given breeding area migrate to the same winter area, and vice versa, then migratory connectivity is 'strong'. At the opposite end of the continuum, if individuals from each breeding region migrate to all wintering area and vice versa, migratory connectivity is 'weak' or 'diffuse'.

Migratory connectivity is important to understand the vulnerability of populations to habitat changes. For King Eiders in western North America, it is important to understand migratory connectivity to elucidate where factors that may have caused population declines on breeding grounds could have been operating.