Ctenucha brunnea
In 3 days ~30% in a week ~50%
Ctenucha brunnea, the brown ctenucha or brown-winged ctenucha, is a moth of the family Erebidae. The species was first described by Richard Harper Stretch in 1872. It is a diurnal moth found in the US from central to southern coastal California. North of that, it is replaced by Ctenucha multifaria.
Adults' bodies are 20–26 millimetres (0.79–1.02 in) in length and blue, with red heads and shoulder markings. The length of the forewings is 18–20 millimetres (0.71–0.79 in). Adults are on wing from mid May to mid July. They feed on the nectar of Heteromeles arbutifolia.
Eggs are round and fade from white to yellow, and laid in rows. The larvae are black with buff-colored or yellow hairs, with two black tufts on the front and rear and an amber or orange head. They feed on Leymus condensatus and other grasses and sedges. The pupae are chestnut in color and wrapped loosely in a cocoon of the larval hairs. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Channel Islands National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | San Diego | 🇺🇸 United States | |
| 2 | Los Angeles | 🇺🇸 United States |
With luck
About 10% of wildlife watchers report a Brown Ctenucha sighting in Channel Islands National Park on a given day, based on 15 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 53rd most-seen of the 131 insects we can rate there. Over three days the chance rises to about 30%, and over a week to about 50%, if each day is a fresh chance.
June and July
In those months about 20% of wildlife watchers report a Brown Ctenucha in Channel Islands National Park on a given day, against under 5% in August to April, the lowest months. Those are among Channel Islands National Park's driest months, with almost no rain against 60 mm in January.
Between 2 and 5 pm
Across all the parks we cover, that three-hour window holds the most Brown Ctenucha sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Only Channel Islands National Park, in our data
Channel Islands National Park is the only park on Wallace's Line with enough records to rate Brown Ctenucha sightings: about 10% of wildlife watchers there report one on a given day.
Same family: Erebidae
The closest relatives of the Brown Ctenucha that you can see in Channel Islands National Park (family Erebidae, Underwing, Tiger, Tussock, and Allied Moths) are Salt Marsh Moth (about 30%), Lophocampa indistincta (about 30%) and Painted Tiger Moth (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Brown Ctenucha is recorded against all the insects logged in Channel Islands National Park (15 verified sightings from 2019 to 2026), 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.
