Modifiers matching insectivore:

• terrestrial,
• avian,
• smaller,
• small,
• nocturnal,
• flying,
• native,
• migrant,
• mammalian,

Simple categories matching migrant:

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