Arctic Louse Fly vs Yellow Swarming Fly

Side-by-side species comparison

Attribute Arctic Louse Fly Yellow Swarming Fly
Scientific Name Ornithomya fringillina Thaumatomyia notata
Order Diptera Diptera
Family Hippoboscidae Chloropidae
Size 4-6 mm 2-2.5 mm
Habitat Tundra & Arctic Grasslands
Diet Parasites Predators
Regions Scandinavia, northern Russia, subarctic Canada, Alaska Europe
Conservation Least Concern Least Concern

Arctic Louse Fly

A flattened, wingless or short-winged parasitic fly that lives among the feathers of Arctic birds. Its laterally flattened body allows it to move easily through plumage. Adults have strong claws for gripping feathers.

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Did You Know?

These flies can survive being transported thousands of kilometers on migratory birds from the Arctic to their wintering grounds.

Yellow Swarming Fly

A tiny yellow fly famous for forming enormous hibernation aggregations in buildings, sometimes numbering millions. Larvae are predatory on root aphids in grassland.

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Did You Know?

Can form hibernation clusters of millions in attic spaces, with individual aggregations weighing several kilograms.