Some individual members of at least some migratory bird species sometimes choose not to migrate. Migration is very often sideways, vertical, even around a loop or route, rather than north/south. There exist multigenerational migrations - where the travel time is longer than one lifespan. One can view some kinds of ecological population establishment - "hopscotch stability" in large moths, say - as existing in a continuum that blends in with migration so called - some kind of cues say "move like this, until encountering that; then do this other." Possible: That cue-response capability (move when cued, move like this, stop when countercued, act in this way now) may be a general root-level module of some kind, hardwired and inheritable, and available to a variety of "cues", "motions", and "actions" - learned, epigenetic, genetic, or any combination of . The question being: what exactly was that choice, that manifested itself as a choice not to migrate?