8 Types of Bats in Washington
Yes, Washington is home to at least 15 bat species. Most common are the big brown bat and little brown myotis. Start your search near water sources like lakes and rivers at dusk during summer months. Look for them emerging from roosts in tree cavities, bridges, or buildings. Washington bats are entirely insectivorous, consuming thousands of mosquitoes and agricultural pests each night. Understanding the types found here helps you predict where and when to spot them during the peak activity season from May through September.
By Tim, founder of Easy Street Markets. I maintain the wildlife database and verify every animal and source myself. Updated July 2, 2026.
Verified species, source iNaturalist
8 types of bats recorded in Washington
8 bat species have a verified observation record in Washington across bats (order Chiroptera), each with at least 10 confirmed sightings. The full list, ranked by how often each is recorded, is below.
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Plus 7 more recorded only rarely (fewer than 10 verified sightings). Counts from verified iNaturalist observations. Photos by iNaturalist observers, reused under the licence each observer chose.
Yes, Washington is home to at least 15 bat species. Most common are the big brown bat and little brown myotis. Start your search near water sources like lakes and rivers at dusk during summer months. Look for them emerging from roosts in tree cavities, bridges, or buildings. Washington bats are entirely insectivorous, consuming thousands of mosquitoes and agricultural pests each night. Understanding the types found here helps you predict where and when to spot them during the peak activity season from May through September.
1. What are the most common bat species in Washington?
Washington hosts a variety of bat species, but you are most likely to spot the big brown bat (Eptesicus fuscus) and the little brown myotis (Myotis lucifugus). Other frequently seen species include the Yuma myotis, California myotis, and the hoary bat. The big brown bat is larger with a wingspan up to 13 inches, while the little brown myotis is smaller and darker. Both are insectivores and emerge at dusk. The Yuma myotis prefers water sources and often roosts in buildings near urban areas. California myotis are small and agile, making them difficult to spot in flight but recognizable by their small size and slow, fluttering wing beats. The hoary bat is a tree-roosting species that migrates through Washington, appearing in spring and fall.
2. How many bat species live year-round in Washington?
Approximately 8 to 10 species are year-round residents or regular migrants through Washington. The big brown bat, little brown myotis, and Yuma myotis are permanent residents. The hoary bat, red bat, and silver-haired bat migrate seasonally through Washington, arriving in spring and departing by late fall. Some species like the long-eared myotis and fringed myotis are year-round but more reclusive. The pallid bat is rare but occasionally recorded in the drier eastern regions. Understanding which species are present during each season helps target your observations to the most active species when you visit.
3. Where in Washington are bats most often seen?
Bats are commonly observed near water bodies such as the Puget Sound, Lake Washington, and the Columbia River. They forage over rivers, ponds, and marshes. You may also spot them in forests and urban areas where old buildings or bridges provide roosting spots. Good starting points include Discovery Park in Seattle, the Skagit River area, and the Okanogan National Forest. Check out ourWashington wildlife pagefor more local sighting tips. The Snoqualmie River, Wenatchee River, and numerous smaller mountain streams also support active bat populations, especially during summer months when insects are most abundant.
4. When is the best time of year or day to see bats in Washington?
The best time to see bats is from late May through early September, when insects are abundant and bat activity peaks. They are crepuscular, so the optimal viewing window is 30 minutes after sunset. Maternity colonies are active in June and July, with pups learning to fly by August. For reliable sightings, visit known roost sites at dusk on a warm, still evening. Late spring through summer offers the longest daylight hours, which means more time to observe bat activity. August is particularly productive as young bats become independent and feed voraciously to prepare for migration or hibernation. Avoid the winter months when most species are hibernating and activity is minimal.
See ourstate animal guidefor the next step.
5. How can you identify different bat species in the field?
Key identification markers include size, ear shape, and fur color. The big brown bat has a blunt nose and a wingspan of 12-16 inches, while the little brown myotis has pointed ears and a wingspan of 9-11 inches. The hoary bat is larger with frosted fur, and the pallid bat has large ears and a pale coat. Use a flashlight with a red filter to avoid disturbing them. For more detailed visual guides, visit ourbat identification page. Size is often the first clue in the field: hoary bats are large and stocky, little brown myotis are compact and dark, and California myotis are delicate and small. Ear shape and position vary significantly between species and become easier to recognize with practice. Fur texture also helps: hoary bats appear frosted or silvery, while most myotis species have glossy brown fur. In flight, wing beat patterns differ by species, hoary bats are slower with broader wings, while myotis species are faster and more erratic.
6. What do bats in Washington eat and where do they roost?
All Washington bats are insectivores, feeding on moths, beetles, flies, and mosquitoes. They roost in tree cavities, under loose bark, in rock crevices, and in man-made structures like attics, barns, and bridges. Some species, like the big brown bat, prefer buildings, while others, like the hoary bat, roost in trees. Maternity roosts can host hundreds of females and are especially common in warm attics during summer. A single bat can consume up to 1,000 mosquitoes in one night, making them valuable natural pest control. Different species have distinct roost preferences: little brown myotis often select caves or mines for hibernation, big brown bats favor buildings and bridges, and tree-roosting species like the hoary bat hang from leaves and branches. Summer roosts may differ from hibernation sites, with females seeking warm locations for nursing pups.
7. What is the difference between maternity and bachelor roosts?
Maternity roosts house pregnant and nursing females during the breeding season, typically from May through August. These roosts are warm and protected, often in attics or warm buildings where pups can develop safely. Males and non-breeding females gather in bachelor roosts, which can be cooler and less protected. Bachelor roosts are often temporary staging areas used during migration. Understanding this distinction helps explain different bat behavior during different parts of the season. Maternity roosts are essential for reproduction and attract concentrated populations of females. If you encounter a roost with many bats in summer, it is likely a maternity colony. Bachelor roosts are scattered and opportunistic, so sightings from these locations are more random.
8. Which Washington bat species are most at risk?
Several species face conservation challenges in Washington. The little brown myotis has declined dramatically due to white-nose syndrome, a fungal disease affecting hibernating bats. The eastern long-eared myotis is rare and listed as a species of concern. The pallid bat is infrequent and restricted to eastern Washington's arid regions. The northern long-eared myotis is also scarce and sensitive to habitat disturbance. Conservation efforts focus on protecting hibernacula and maintaining summer roost habitat. White-nose syndrome, caused by the fungus Pseudogymnoascus destructans, has devastated populations in eastern North America and is slowly spreading westward. You can help by never handling bats or entering caves during hibernation season, and by supporting organizations working to protect these species.
9. How do Washington bats prepare for winter?
In late summer and early fall, bats enter a feeding frenzy called hyperphagia, consuming as many insects as possible to build fat reserves. They seek hibernacula such as caves, mines, and buildings where temperatures remain stable through winter. Some species, like the hoary bat and red bat, migrate south rather than hibernate locally. By late November, most bats are in their hibernation sites, where they enter torpor, lowering their body temperature and metabolic rate to survive months without food. Torpor allows bats to conserve enormous amounts of energy. A bat that weighs 7 grams needs to gain about 3 grams of fat to survive winter hibernation. Migration routes span hundreds of miles, with some hoary bats traveling from Canada to Mexico.
10. What should you do if you find an injured or grounded bat?
Never handle a bat with bare hands, as they can carry rabies. If you find a grounded bat that appears weak or injured, place a small container over it to protect it from predators. Contact a local wildlife rehabilitator or animal control for assistance. Many bats are simply tired and need a safe place to rest; moving them to a sheltered spot like a shrub or wall can help. If possible, provide information about the location and the bat's condition to a rehabilitator. Washington has several licensed wildlife rehabilitation centers equipped to care for bats. Handling protocols are important for your safety and the bat's wellbeing. Even if a bat appears docile, rabies exposure requires post-exposure prophylaxis, a serious medical intervention.
11. Which Washington bats are easiest to spot for a beginner?
The big brown bat is your best target as a beginner. They are large, emerge early at dusk before it gets fully dark, and tolerate human presence near buildings and bridges. Little brown myotis are also relatively common and emerge shortly after dark. Visit popular bat-watching spots like bridges over rivers on warm evenings. Bring a red-filtered flashlight and binoculars. Big brown bats often hunt in open spaces where they are visible against the twilight sky. Little brown myotis may be harder to see in their details but create distinctive silhouettes in flight. Both species are forgiving targets for learning identification, and successful sightings build confidence for spotting rarer species. Avoid the temptation to shine bright lights at bats, as this can disrupt their hunting behavior.
Show your bat appreciation with bat-themed gear
After spotting these amazing creatures, you can celebrate your experience with some bat-themed items. Easy Street Markets offers a variety of bat apparel and accessories for fellow wildlife enthusiasts (without the word!). Check out these top picks:
Cute Bat Sticker
A perfect way to show your love for bats on laptops, water bottles, or journals.Check Price and Availability
Bat Animal Short-Sleeve T-Shirt
A comfortable t-shirt featuring a realistic bat graphic. Great for casual wear or field days.Check Price and Availability
Baby Bat Cartoon T-Shirt
A cute cartoon bat shirt that makes an excellent gift. Soft and stylish.Check Price and Availability
For more options, browse our full collection ofbat t-shirts.
Gear and field guides
Frequently asked questions
1. What are the most common bat species in Washington?+
Washington hosts a variety of bat species, but you are most likely to spot the big brown bat (Eptesicus fuscus) and the little brown myotis (Myotis lucifugus). Other frequently seen species include the Yuma myotis, California myotis, and the hoary bat. The big brown bat is larger with a wingspan up to 13 inches, while the little brown myotis is smaller and darker. Both are insectivores and emerge at dusk. The Yuma myotis prefers water sources and often roosts in buildings near urban areas. California myotis are small and agile, making them difficult to spot in flight but recognizable by their small size and slow, fluttering wing beats. The hoary bat is a tree-roosting species that migrates through Washington, appearing in spring and fall.
2. How many bat species live year-round in Washington?+
Approximately 8 to 10 species are year-round residents or regular migrants through Washington. The big brown bat, little brown myotis, and Yuma myotis are permanent residents. The hoary bat, red bat, and silver-haired bat migrate seasonally through Washington, arriving in spring and departing by late fall. Some species like the long-eared myotis and fringed myotis are year-round but more reclusive. The pallid bat is rare but occasionally recorded in the drier eastern regions. Understanding which species are present during each season helps target your observations to the most active species when you visit.
3. Where in Washington are bats most often seen?+
Bats are commonly observed near water bodies such as the Puget Sound, Lake Washington, and the Columbia River. They forage over rivers, ponds, and marshes. You may also spot them in forests and urban areas where old buildings or bridges provide roosting spots. Good starting points include Discovery Park in Seattle, the Skagit River area, and the Okanogan National Forest. Check out ourWashington wildlife pagefor more local sighting tips. The Snoqualmie River, Wenatchee River, and numerous smaller mountain streams also support active bat populations, especially during summer months when insects are most abundant.
4. When is the best time of year or day to see bats in Washington?+
The best time to see bats is from late May through early September, when insects are abundant and bat activity peaks. They are crepuscular, so the optimal viewing window is 30 minutes after sunset. Maternity colonies are active in June and July, with pups learning to fly by August. For reliable sightings, visit known roost sites at dusk on a warm, still evening. Late spring through summer offers the longest daylight hours, which means more time to observe bat activity. August is particularly productive as young bats become independent and feed voraciously to prepare for migration or hibernation. Avoid the winter months when most species are hibernating and activity is minimal. See ourstate animal guidefor the next step.
5. How can you identify different bat species in the field?+
Key identification markers include size, ear shape, and fur color. The big brown bat has a blunt nose and a wingspan of 12-16 inches, while the little brown myotis has pointed ears and a wingspan of 9-11 inches. The hoary bat is larger with frosted fur, and the pallid bat has large ears and a pale coat. Use a flashlight with a red filter to avoid disturbing them. For more detailed visual guides, visit ourbat identification page. Size is often the first clue in the field: hoary bats are large and stocky, little brown myotis are compact and dark, and California myotis are delicate and small. Ear shape and position vary significantly between species and become easier to recognize with practice. Fur texture also helps: hoary bats appear frosted or silvery, while most myotis species have glossy brown fur. In flight, wing beat patterns differ by species, hoary bats are slower with broader wings, while myotis species are faster and more erratic.
6. What do bats in Washington eat and where do they roost?+
All Washington bats are insectivores, feeding on moths, beetles, flies, and mosquitoes. They roost in tree cavities, under loose bark, in rock crevices, and in man-made structures like attics, barns, and bridges. Some species, like the big brown bat, prefer buildings, while others, like the hoary bat, roost in trees. Maternity roosts can host hundreds of females and are especially common in warm attics during summer. A single bat can consume up to 1,000 mosquitoes in one night, making them valuable natural pest control. Different species have distinct roost preferences: little brown myotis often select caves or mines for hibernation, big brown bats favor buildings and bridges, and tree-roosting species like the hoary bat hang from leaves and branches. Summer roosts may differ from hibernation sites, with females seeking warm locations for nursing pups.
7. What is the difference between maternity and bachelor roosts?+
Maternity roosts house pregnant and nursing females during the breeding season, typically from May through August. These roosts are warm and protected, often in attics or warm buildings where pups can develop safely. Males and non-breeding females gather in bachelor roosts, which can be cooler and less protected. Bachelor roosts are often temporary staging areas used during migration. Understanding this distinction helps explain different bat behavior during different parts of the season. Maternity roosts are essential for reproduction and attract concentrated populations of females. If you encounter a roost with many bats in summer, it is likely a maternity colony. Bachelor roosts are scattered and opportunistic, so sightings from these locations are more random.
8. Which Washington bat species are most at risk?+
Several species face conservation challenges in Washington. The little brown myotis has declined dramatically due to white-nose syndrome, a fungal disease affecting hibernating bats. The eastern long-eared myotis is rare and listed as a species of concern. The pallid bat is infrequent and restricted to eastern Washington's arid regions. The northern long-eared myotis is also scarce and sensitive to habitat disturbance. Conservation efforts focus on protecting hibernacula and maintaining summer roost habitat. White-nose syndrome, caused by the fungus Pseudogymnoascus destructans, has devastated populations in eastern North America and is slowly spreading westward. You can help by never handling bats or entering caves during hibernation season, and by supporting organizations working to protect these species.
9. How do Washington bats prepare for winter?+
In late summer and early fall, bats enter a feeding frenzy called hyperphagia, consuming as many insects as possible to build fat reserves. They seek hibernacula such as caves, mines, and buildings where temperatures remain stable through winter. Some species, like the hoary bat and red bat, migrate south rather than hibernate locally. By late November, most bats are in their hibernation sites, where they enter torpor, lowering their body temperature and metabolic rate to survive months without food. Torpor allows bats to conserve enormous amounts of energy. A bat that weighs 7 grams needs to gain about 3 grams of fat to survive winter hibernation. Migration routes span hundreds of miles, with some hoary bats traveling from Canada to Mexico.
10. What should you do if you find an injured or grounded bat?+
Never handle a bat with bare hands, as they can carry rabies. If you find a grounded bat that appears weak or injured, place a small container over it to protect it from predators. Contact a local wildlife rehabilitator or animal control for assistance. Many bats are simply tired and need a safe place to rest; moving them to a sheltered spot like a shrub or wall can help. If possible, provide information about the location and the bat's condition to a rehabilitator. Washington has several licensed wildlife rehabilitation centers equipped to care for bats. Handling protocols are important for your safety and the bat's wellbeing. Even if a bat appears docile, rabies exposure requires post-exposure prophylaxis, a serious medical intervention.
11. Which Washington bats are easiest to spot for a beginner?+
The big brown bat is your best target as a beginner. They are large, emerge early at dusk before it gets fully dark, and tolerate human presence near buildings and bridges. Little brown myotis are also relatively common and emerge shortly after dark. Visit popular bat-watching spots like bridges over rivers on warm evenings. Bring a red-filtered flashlight and binoculars. Big brown bats often hunt in open spaces where they are visible against the twilight sky. Little brown myotis may be harder to see in their details but create distinctive silhouettes in flight. Both species are forgiving targets for learning identification, and successful sightings build confidence for spotting rarer species. Avoid the temptation to shine bright lights at bats, as this can disrupt their hunting behavior.
Keep exploring
More places to see bat
More wildlife in Washington