Hydrobates homochroa
Silhouette: Rachel Shoop · PhyloPic
In 3 days <5%
The ashy storm petrel (Hydrobates homochroa) is a small, scarce seabird of the storm petrel family Hydrobatidae. It breeds colonially on islands off the coasts of California and Mexico, and is one of six species of storm petrel that live and feed in the rich California Current system.
The ashy storm petrel was first described by American ornithologist Elliott Coues in 1864. Both its common and scientific name, homochroa, "uniformly colored", from Ancient Greek (h)omoia (όμοια), "alike" + "chroma" (χρώμα) "color", come from its coloration.
It was formerly defined in the genus Oceanodroma before that genus was synonymized with Hydrobates. This is a small, uniformly sooty-brown storm petrel with a forked tail, closely resembling the black storm petrel, but it is smaller and has a more fluttering style of flight, with the upstroke only becoming horizontal to the body before beginning the downstroke (other storm petrels in its range have a higher upstroke).
It is a gregarious bird at sea, feeding nocturnally on cephalopods, fish (particularly the deep-sea myctophids, which rise to the sea's surface at night) and euphausiid krill such as Thysanoessa... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | San Diego | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report an Ashy Storm-Petrel sighting in San Diego on a given day, based on 30 verified sightings from GBIF citizen-science data. It is the 341st most-seen of the 386 birds we can rate there. Over three days the chance rises to under 5%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report an Ashy Storm-Petrel in San Diego on a given day, so our monthly data shows no clear season.
Only San Diego, in our data
San Diego is the only city on Wallace's Line with enough records to rate Ashy Storm-Petrel sightings: under 5% of wildlife watchers there report one on a given day.
GBIF citizen-science records
It is estimated from how often the Ashy Storm-Petrel is recorded against all the birds logged in San Diego (30 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
