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Side-by-Side Comparison

Attribute	Ainley's Storm-petrel	Monteiro's Storm-petrel
Scientific Name	Hydrobates cheimomnestes	Hydrobates monteiroi
Order	Procellariiformes	Procellariiformes
Family	Hydrobatidae	Hydrobatidae
Conservation Status	Vulnerable	Vulnerable
Length	—	—
Wingspan	30.1 cm (11.9 in)	30.6 cm (12.0 in)
Weight	41.15 g (1.45 oz)	45.5 g (1.60 oz)
Diet	--	--
Clutch Size	1	1
Population Trend	—	—

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Habitat Comparison

Shared Habitats

None

Ainley's Storm-petrel only

None

Monteiro's Storm-petrel only

🏖️ Coastal

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Conservation Status

Vulnerable

Ainley's Storm-petrel

Vulnerable

Monteiro's Storm-petrel

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About These Birds

Ainley's Storm-petrel

Ainley's Storm-petrel, 19–21 cm, is a recently described species breeding on the Channel Islands off California, present in winter — unusual among storm-petrels which typically breed in summer. Dark overall, white rump with central grey stripe. Vulnerable; small population and restricted range.

Monteiro's Storm-petrel

Monteiro's Storm-petrel, 19–21 cm, breeds exclusively on Graciosa Island in the Azores, wintering in the central North Atlantic. Recently split from Band-rumped Storm-petrel; breeds in a different season (July–November vs March–April for Castro's). Near Threatened; very small island-restricted population.

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More Birds to Explore

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