Modifiers matching insectivore:

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

Simple categories matching migrant:

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