Modifiers matching warbler:

• migrant,
• common,
• breeding,

Simple categories matching migrant:

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