Have you ever noticed a large, colorful insect hovering near your porch light at dusk? Northern California hosts an incredible diversity of moths in Northern California, from tiny clearwings that mimic hummingbirds to massive silk moths with wingspans exceeding five inches.
While many people overlook these nocturnal creatures in favor of their butterfly cousins, moths play crucial roles as pollinators, food sources for wildlife, and indicators of ecosystem health.
You’ll discover how to identify 25 of the most commonly encountered species across the region, from the fog-shrouded Bay Area to the Sierra Nevada foothills, with straightforward descriptions that focus on the distinctive features that make each species recognizable.
1. Western Poplar Sphinx Moth
The western poplar sphinx moth (Pachysphinx occidentalis) ranks among the larger sphinx moths found throughout Northern California. Adults display soft gray-brown coloring with subtle darker bands across their forewings and a wingspan reaching 3 to 4 inches. Their thick, furry bodies and swept-back wing position make them aerodynamic fliers capable of rapid movement.
You’ll typically encounter these moths from May through August near riparian areas where their host plants thrive. Cottonwood and poplar trees serve as the primary food sources for their bright green caterpillars, which can grow up to 3.5 inches long before pupating. The caterpillars feature a distinctive horn at their rear end, a characteristic trait of sphinx moth larvae.
Pro Tip: Look for western poplar sphinx moths around dusk when they become active. Their swift, direct flight pattern distinguishes them from other large moths that tend to flutter more erratically.
2. Hummingbird Clearwing Moth
Despite its name, the hummingbird clearwing moth (Hemaris thysbe) is indeed a moth, not a bird. This fascinating daytime flier mimics hummingbird behavior so convincingly that most people mistake it for the real thing. The species features transparent wings bordered with reddish-brown margins, an olive-green to golden-brown body, and a wingspan of 1.5 to 2 inches.
Active during daylight hours from April through August, these moths hover at flowers while feeding on nectar with their long proboscis. You’ll spot them in gardens, meadows, and woodland edges where their preferred nectar sources bloom. Honeysuckle, bee balm, and phlox attract them reliably. Their caterpillars feed on honeysuckle and snowberry plants, appearing as plump green larvae with yellow and black markings.
3. Snowberry Clearwing Moth
The snowberry clearwing moth (Hemaris diffinis) closely resembles its hummingbird clearwing cousin but displays subtle differences that help with identification. This species has clear wings with dark borders, a black and yellow banded abdomen, and measures 1.3 to 2 inches across. The black segments on the abdomen appear more prominent than on the hummingbird clearwing.
These moths frequent gardens and open areas throughout the warm months, particularly where snowberry and honeysuckle plants grow. They demonstrate the same hovering feeding behavior as other clearwing species, making them delightful to observe. Their flight season extends from May through September in Northern California, with peak activity during midday hours when temperatures warm.
Key Insight: Both clearwing species lose the scales on their wings after their first flight, creating the transparent appearance that gives them their name.
4. Giant Leopard Moth
The giant leopard moth (Hypercompe scribonia) makes a striking impression with its bold patterning. Adults showcase pure white wings decorated with dark blue-black spots creating a leopard-like appearance, hence the common name. Their wingspan reaches 2 to 3 inches, and their abdomen displays brilliant metallic blue with orange bands when viewed from above.
You’ll encounter these moths from April through September, with the caterpillar stage being equally distinctive. The “woolly bear” caterpillars appear entirely black with red bands between their segments and long black bristles. They feed on a wide variety of plants including plantain, dandelion, and various garden vegetables. When threatened, both caterpillars and adults curl up defensively.
5. Virgin Tiger Moth
The virgin tiger moth (Grammia virgo) belongs to the tiger moth family and displays characteristic warning coloration. Adults have creamy white to pale yellow forewings marked with black spots and lines, while their hindwings reveal bright pink or red coloring with black spots. This color combination spans a 1.5 to 2.5 inch wingspan.
Active from May through September, these moths inhabit meadows, grasslands, and open woodlands throughout Northern California. Their caterpillars are “woolly bears” covered in dense black and reddish-brown hairs. The bright coloring serves as aposematic warning to predators, signaling that the moths contain distasteful compounds acquired from their host plants during the larval stage.
6. Banded Tussock Moth
The banded tussock moth (Halysidota tessellaris) presents a more subdued appearance than many tiger moths. Adults feature pale yellow to cream-colored wings with faint darker bands and spots, measuring 1.5 to 2 inches across. Their hairy bodies match the pale coloring of their wings.
However, the caterpillars steal the show with their spectacular appearance. Tussock moth larvae display cream-colored bodies decorated with black tufts along the sides and four prominent white or yellow tufts on their backs. Long black hairs extend from both ends. These eye-catching caterpillars feed on deciduous trees including oak, birch, and willow from spring through early fall. The adults fly from May through August.
Common Mistake: Don’t touch tussock moth caterpillars. Those attractive hairs can cause skin irritation and allergic reactions in sensitive individuals.
7. Salt Marsh Moth
The salt marsh moth (Estigmene acrea) adapts to various habitats despite its name. Adults display considerable variation in appearance, with coloring ranging from pure white to yellow or orange. Males typically show more yellowish tones with small dark spots on their wings, while females appear predominantly white. Their wingspan measures 1.5 to 2.5 inches.
These moths produce multiple generations per year in Northern California, with adults present from May through October. The caterpillars, known as “salt marsh caterpillars,” feature dense coats of long hairs in colors varying from yellow to brown to black. They feed on an extremely wide range of plants, making them common in gardens, agricultural areas, and wild spaces. The caterpillars have an impressive defense mechanism: when disturbed, they can release silk strands and “windsurf” away from danger.
8. Isabella Tiger Moth
The Isabella tiger moth (Pyrrharctia isabella) achieves fame primarily through its caterpillar form, the banded woolly bear. Adults appear more modest with yellow-orange to buff-colored wings sparsely dotted with black spots. Their wingspan ranges from 1.75 to 2.5 inches, and their bodies are covered in orange-yellow fur.
You’ll recognize the caterpillars more readily than the adults. These familiar fuzzy caterpillars display black ends with a rusty orange-brown middle band, though the proportions vary among individuals. Folklore suggests the band width predicts winter severity, though no scientific evidence supports this claim. The species overwinters as a caterpillar, producing a natural antifreeze that allows survival in freezing temperatures. Adults emerge and fly from May through July.
9. California Oak Moth
The California oak moth (Phryganidia californica) holds special significance as a native species endemic to the West Coast. Adults are small, delicate moths with gray-brown wings featuring subtle darker markings and a wingspan of only 0.75 to 1 inch. Their appearance might seem unremarkable, but their ecological impact is substantial.
These moths produce two generations annually: one in spring and another in late summer to fall. The caterpillars can completely defoliate oak trees, particularly coast live oak and interior live oak. While alarming to homeowners, this defoliation rarely kills healthy trees, which typically recover and produce new leaves. The caterpillars are pale green with black stripes running lengthwise. Both adults and larvae remain active during daylight hours, unusual behavior for moths.
10. Luna Moth
The luna moth (Actias luna) ranks among North America’s most spectacular moths. These large silk moths display pale green wings with transparent eyespots bordered in yellow, pink, and purple. Their hindwings extend into long, graceful tails, and their wingspan can reach 3 to 4.5 inches. Males have feathery antennae noticeably larger than females.
Despite their size and beauty, luna moths are challenging to observe. Adults emerge from cocoons in late spring and summer but live only about one week. During this brief adult stage, they don’t feed at all, existing solely to reproduce. You’ll most likely spot them at night near lights, though they’re less attracted to artificial lighting than many moth species. Their caterpillars feed on various deciduous trees including walnut, sweetgum, and persimmon.
Important Note: Luna moths have no mouth parts as adults. Their entire adult life focuses on reproduction, making their week-long existence a race against time.
11. Polyphemus Moth
The polyphemus moth (Antheraea polyphemus) earns recognition as one of the largest moths in Northern California. These impressive silk moths display reddish-brown to yellowish-brown coloring with large, striking eyespots on both fore and hindwings. The eyespots feature concentric circles of black, blue, yellow, and pink, creating a mesmerizing pattern. Their wingspan typically measures 4 to 6 inches.
You’ll encounter these moths from April through September, with adults living only 3 to 4 days without feeding. The giant caterpillars grow up to 3 inches long, appearing bright green with diagonal white lines and small orange tubercles along their sides. They feed on a remarkable variety of trees including oak, maple, willow, and various fruit trees. When threatened, the caterpillars make clicking sounds by rubbing their mandibles together.
12. Cecropia Moth
The cecropia moth (Hyalophora cecropia) claims the title of largest native moth in North America. These magnificent creatures showcase reddish-brown wings banded with white, tan, and red, plus prominent crescent-shaped white spots near the center of each wing. Their wingspan can reach an impressive 5 to 7 inches, making them unmistakable when encountered.
Active from April through June, cecropia moths emerge from winter cocoons wrapped in silk and attached to tree branches. Like other giant silk moths, adults don’t feed and survive only one to two weeks. Their caterpillars rank among the largest found in the region, growing up to 4.5 inches long. The larvae appear bright green decorated with blue, yellow, and red tubercles along their bodies. They feed on various trees including maple, cherry, plum, and willow.
13. Io Moth
The io moth (Automeris io) demonstrates dramatic sexual dimorphism in coloring. Males display bright yellow forewings and hindwings, while females show reddish-brown to purplish-brown forewings with matching hindwings. Both sexes feature large, prominent eyespots on their hindwings with black pupils surrounded by blue, white, and yellow rings. Their wingspan ranges from 2 to 3 inches.
These moths fly from April through September in Northern California. The caterpillars pose a more significant concern than the beautiful adults. Bright green with distinctive red and white stripes running along their sides, io moth caterpillars are covered in branched spines that deliver a painful, venomous sting. The pain can be intense and may last for hours. The caterpillars feed on various plants including oak, willow, maple, and clover.
Common Mistake: Never handle io moth caterpillars. The venomous spines cause immediate, severe pain and can trigger allergic reactions.
14. Imperial Moth
The imperial moth (Eacles imperialis) lives up to its regal name with impressive size and variable coloring. Adults display yellow wings marked with purplish-brown to pinkish-purple spots and blotches, though the amount of purple coloring varies considerably among individuals. Some appear mostly yellow while others show extensive purple markings. Their wingspan reaches 3 to 7 inches, with females noticeably larger than males.
You’ll spot these moths from June through September in areas with mixed deciduous and coniferous forests. The caterpillars grow large, reaching up to 4 inches in length, and change appearance as they mature. Young larvae appear orange with black crossbands, while mature caterpillars typically show green or brown coloring with yellow spots and short spines. They feed on various trees including pine, oak, maple, and sassafras.
15. White-Lined Sphinx Moth
The white-lined sphinx moth (Hyles lineata) ranks as one of the most commonly observed sphinx moths in Northern California. These medium to large moths feature olive-brown forewings with thick tan stripes intersected by thin white lines that give the species its name. Their hindwings display black coloring with bright pink or reddish bands through the middle. With a wingspan of 2.5 to 3.5 inches, they’re easily noticed.
Active from March through October, these moths often hover at flowers during dawn, dusk, or even in bright sunlight, leading many observers to mistake them for hummingbirds. They exhibit remarkable speed and maneuverability, visiting flowers for nectar using their long proboscis. The caterpillars show variable coloring ranging from green to black with distinct yellow or white spots along their sides and the characteristic sphinx moth horn at the rear.
16. Tersa Sphinx Moth
The tersa sphinx moth (Xylophanes tersa) presents an elegant, streamlined appearance. Adults display brown to gray-brown forewings marked with complex patterns of light and dark patches, plus a distinctive zigzag line running from wing tip to base. Their hindwings show brown coloring with a tan or buff-colored border. The wingspan measures 2.25 to 3 inches.
These moths demonstrate a more southerly distribution but appear in warmer parts of Northern California from May through October. They feed at flowers during twilight hours, showing particular fondness for petunias, honeysuckle, and jasmine. The caterpillars are unique among sphinx moths, appearing remarkably slender with large, false eyespots on their abdominal segments. They feed primarily on plants in the madder family, including pentas and bouvardia.
17. Vine Sphinx Moth
The vine sphinx moth (Eumorpha vitis) displays attractive coloring and patterns. Adults feature brown to gray-brown forewings with darker brown patches and lighter tan or pinkish highlights. Their hindwings show rose-pink to salmon-pink coloring, particularly vibrant near the body. The wingspan ranges from 2 to 3.5 inches.
You’ll encounter these moths from May through September in areas where grape vines and Virginia creeper grow. The caterpillars demonstrate color variation, appearing in green or brown forms, both featuring seven diagonal white or yellow stripes on their sides. The green form is more common. When disturbed, the larvae can retract their head into the thorax, causing the front segments to appear swollen and the eyespots to become more prominent, creating an intimidating snake-like appearance.
18. Achemon Sphinx Moth
The achemon sphinx moth (Eumorpha achemon) ranks among the more colorful sphinx moths found in the region. Adults display brown forewings mottled with pink and tan patches, creating a camouflaged appearance. Their hindwings feature deep pink coloring that may appear almost red in some individuals. The wingspan measures 3 to 4 inches.
Active from May through October, these moths visit flowers at night, particularly attracted to petunias, honeysuckle, and evening primrose. The caterpillars show interesting developmental changes. Young larvae possess the typical sphinx moth horn, but later instars lose this structure, replacing it with a glossy eyespot. Mature caterpillars appear brown or green with six white or yellow oval spots along their sides. They feed on grape vines and Virginia creeper.
19. Blinded Sphinx Moth
The blinded sphinx moth (Paonias excaecata) gets its unusual common name from the eyespots on its hindwings, which appear “blind” or pupil-less compared to other species. Adults showcase mottled gray-brown forewings with subtle pink, tan, and darker brown markings. Their hindwings display yellowish-tan coloring with large, diffuse gray-blue eyespots. The wingspan ranges from 2 to 3 inches.
These moths fly from May through August, typically in wooded areas near their host plants. You’ll most often see them at night when they visit flowers or rest on tree trunks during the day. The caterpillars are bright green with diagonal white stripes on their sides and a bright blue or green horn at the rear. They feed on various trees and shrubs including willow, poplar, cherry, and birch.
20. Pandora Sphinx Moth
The pandora sphinx moth (Eumorpha pandorus) presents one of the most beautiful color combinations among sphinx moths. Adults feature olive-green forewings with irregular patches of pink and lighter green, creating an elegant pattern. Their hindwings show rich pink to rose coloring. This striking species has a wingspan of 3.25 to 4.5 inches.
You’ll spot these moths from June through October in areas with grape vines and Virginia creeper, the primary host plants for their caterpillars. The large caterpillars display variable coloring in green or burgundy-brown forms, both featuring prominent white or yellow oval spots along their sides. The caterpillars are smooth and plump, reaching up to 3 inches in length. Adults visit flowers at dusk and throughout the night.
Key Insight: The green coloring on pandora sphinx moth wings comes from a combination of yellow and blue scales. As the moths age and scales wear away, the wings may appear more brown or pink.
21. Painted Tiger Moth
The painted tiger moth (Arachnis picta) displays bold patterns befitting the tiger moth family. Adults showcase black forewings decorated with intricate patterns of white or cream-colored patches and lines, while their hindwings reveal bright orange or red coloring marked with large black spots. Their wingspan measures 1.5 to 2.5 inches.
These moths fly from April through September in meadows, grasslands, and open woodlands. The caterpillars appear as typical “woolly bears” covered in long, dense hairs colored black with reddish-brown segments. They feed on various low-growing plants including lupine, clovers, and various wildflowers. Like other tiger moths, this species contains compounds that make them distasteful to many predators, with their bright coloring serving as a warning.
22. Cabbage Looper Moth
The cabbage looper moth (Trichoplusia ni) earns its name from the caterpillar’s distinctive looping movement and plant preferences. Adults appear relatively plain with mottled brown and gray forewings marked by a distinctive silvery figure-eight or comma-shaped spot near the center. Their hindwings show dark brown coloring with lighter fringes. The wingspan measures 1 to 1.5 inches.
Active throughout the warm months, these moths produce multiple generations per year in Northern California’s mild climate. The caterpillars cause significant agricultural damage, feeding on cabbage, broccoli, cauliflower, and related crops. The larvae are pale green with thin white stripes along their sides and move in a characteristic looping motion due to having fewer prolegs than most caterpillars. Gardeners often consider them major pests.
23. Fall Armyworm Moth
The fall armyworm moth (Spodoptera frugiperda) represents an important agricultural pest species. Adults display mottled gray to brown forewings with complex patterns including light and dark patches and subtle white markings. Males typically show more distinct patterns than females. Their hindwings are silvery-white with dark borders. The wingspan ranges from 1.5 to 1.75 inches.
These moths fly year-round in warmer areas of Northern California, with peak populations in late summer and fall. The caterpillars cause extensive damage to grasses, corn, and various other crops. Mature larvae appear dark with distinctive yellow inverted Y marks on their head capsules and four dark spots forming a square on the final abdominal segment. They earned their “armyworm” name because they travel in large groups, devastating crops in their path.
24. Yellow Underwing Moth
The yellow underwing moth (Noctua pronuba) originated in Europe but established populations in Northern California in recent decades. Adults feature mottled brown forewings with subtle darker and lighter patches creating excellent camouflage. Their hindwings display bright yellow coloring with a thick black border along the outer edge. The wingspan measures 1.75 to 2.5 inches.
You’ll encounter these moths from June through October. They rest during the day on tree trunks or under debris where their brown forewings provide camouflage. When disturbed, they flash their bright yellow hindwings, startling potential predators. The caterpillars are plump, brown or green with darker mottling, and feed nocturnally on various plants including vegetables, flowers, and grasses. They hide in soil or under vegetation during daylight hours.
25. Melonworm Moth
The melonworm moth (Diaphania hyalinata) displays an elegant appearance with its pearly white wings. Adults feature lustrous white wings with a satiny sheen, broad black borders along the outer edges, and a black patch at the tip of their forewings. Their bodies appear elongated with black and white banding. The wingspan ranges from 1 to 1.5 inches.
These moths thrive in warmer areas and produce multiple generations throughout the growing season. The caterpillars are yellowish-green with two white stripes running along their sides and cause damage to melons, squash, and other cucurbit crops. Despite being considered agricultural pests, the adults are quite beautiful and are sometimes confused with clearwing moths due to their relatively translucent wings and hovering flight behavior.
Northern California’s moth diversity reflects the region’s varied habitats, from coastal areas to mountain forests.
While these 25 species represent some of the most commonly encountered moths, hundreds of additional species inhabit the region, each playing unique ecological roles.
The next time you spot a moth at your porch light or notice unusual caterpillars on your plants, take a moment to observe the intricate patterns and behaviors that make these nocturnal insects fascinating subjects for nature study. You now have the identification knowledge to recognize the most frequent visitors to your area.
