Storm-petrels are rather small and often dark colored tubenoses with a world wide distribution. All have fine black bills with very pronounced tubes. Storm Petrels are separated in two groups: the long legged, Southern Hemisphere birds subfamily Oceanitinae and the shorter legged species of more northern seas the subfamily Hydrobatinae. The first groups shows more morphological differences than the second. The genera are characterised on colour patterns, the condition of the nasal tubes, tail shape, structure of claws and proportions of the leg bones. The genus Oceanodroma consists of medium-sized petrels; plumage dark or greyish, often with pale rumps; tail more or less forked; tarsus short , middle toe with claw and scutellate; claws narrow.
Listen to the sound of Ashy Storm-petrel
Copyright remark: Most sounds derived from xeno-canto
recorded by UCSC CCAL
|wingspan min.:||46||cm||wingspan max.:||48||cm|
|size min.:||20||cm||size max.:||21||cm|
|incubation min.:||44||days||incubation max.:||45||days|
|fledging min.:||82||days||fledging max.:||84||days|
on rocky islands with abundant crevices for nesting.
nesting is not synchronized; egg-laying may occur any time late April to mid-July, rarely to September. Before eggs are laid, both members of pair may spend time in nest chambers, giving trilling and twittering songs.
Nest: Site is in natural cavity or crevice under rock piles, under driftwood, or in old burrow of other species; usually no nest lining added.
Clutch 1. White or with faint reddish brown dots. Incubation is by both sexes, averages about 44 days.
Young: Probably both parents feed young, by regurgitation. Young leaves nest and goes to sea on average about 76 days after hatching.
Behavior: Forages mostly by hovering or skimming low over water and taking items from surface.
In fall, a high percentage of total population concentrates on Monterey Bay, California. Some may be present in California waters at all seasons, but at northern end of range is least numerous in early winter.