Modifiers matching visa:

• permanent,
• resident,
• valid,
• migrant,
• temporary,

Simple categories matching migrant:

• labourer,
• bird,
• group,
• insectivore,
• visa,
• thrush,
• language,
• passerine,
• sparrow,
• worker,
• songbird,
• population,
• sandpiper,
• waterbird,
• shorebird,
• finch,
• warbler,
• organization,
• fish,