In honor of the SuperbOwl Sunday, we wanted to share a delightful compilation of facts, information, and photos of Northern California’s varied owl species. Included you will find the Northern Spotted Owl, the Great Horned Owl, the Short-eared Owl, and the Northern Pygmy Owl, among others. Sit back with a cup of tea and learn about the incredible owls you may hear or see in our area! This article was written by our wonderful intern, Bente Jansen.
Northern Spotted Owl (Strix occidentalis caurina)
Northern Spotted Owls reside in old-growth forests in northern California, southern British Columbia and the Pacific Northwest. As one of three subspecies of spotted owl, the Northern Spotted Owl does not migrate, but will occasionally shift their range in response to seasonal changes. Northern Spotted Owls are also one of the few owls that have dark brown eyes in comparison to yellow or red. They are an indicator species for the health of the old growth ecosystems they reside in, along with many other species such as the Marbled Murrelet. Northern Spotted Owl pairs do not make their own nest as many other owls; however, unlike most owls the owl pairs also do not nest every year, and are also not successful everytime they do nest. Unfortunately, the Northern Spotted Owls have been experiencing an ongoing decline in their populations due to habitat loss from unsustainable timber practices and competition from the invasive Barred Owl. These large, territorial owls have been listed as “Threatened” under the Endangered Species Act since 1990. Although there have been efforts to assist the Northern Spotted Owl, such as Barred Owl removal and critical habitat designations, their populations continue to decrease and their habitats destroyed. According to the American Bird Conservancy in 2015, “in Oregon’s Coast Range study area, the percentage of sites with spotted owl detection has declined from a high of 88 percent in 1991 to a low of 23 percent in 2013.” As an indicator and keystone species, the Northern Spotted Owl is an extremely important species for the perpetuation of biodiversity and a healthy ecosystem.
Great-horned Owl (Bubo virginianus)
Often seen perching high up at dusk, the Great-horned Owl is the most widespread owl in North America. These large owls, about 22 inches in length, reside in a variety of habitats including forests, urban areas and deserts. As a skilled predator with a large appetite, the Great-horned Owl often feasts on large prey such as rabbits and squirrels. The Great-horned Owls have one of the most diverse diets of all North American Owls; they have even been recorded to eat other Great-horned Owls. As most owls, they are clueless about nest building, and don’t build their own nest but rather use abandoned nest in a tree, cliff or rocky crevice. Once they are adults, the Great-horned Owl has no natural predators and has been recorded to live up to 28 years in the wild.
Barn Owl (Tyto alba)
Often mistaken as a Snowy Owl, Barn Owls are classically identified by their heart-shaped faces. Barn Owls do not build their own nests, but rather lay their eggs on bare surface in a cave or barn or attic. They are usually nocturnal hunters and mainly prey on rats and mice. Because of the shape of their wings and feather structure, Barn Owls are extremely skilled at flying silently and gliding for long periods of time. Because of its ability to hear the smallest rustle made by their rodent prey from up to ten feet above the ground and their stealthy flight ability, the Barn Owl is a talented predator. Unlike many bird species, an interesting characteristic of Barn Owls is their dedication to their partner. Typically Barn Owls will stay monogamous for life or until one of the partners passes away.
Western Screech-Owl (Otus kennicottii)
Once considered to be the same species as the Eastern Screech-Owl, the Western Screech-Owl can be found in deserts, open woods and suburban parks. Although the Western Screech-owl avoids higher elevations and extreme desert conditions, their range is quite large and covers from Southeastern Alaska all the way to Arizona. Well-camouflaged in the cavities of trees, these owls often go undetected. When threatened, the Western Screech-owl will stretch its body and tighten its feathers so as to look like a branch stub. Although a smaller owl species, they have been observed taking prey larger than themselves, such as cottontail rabbits.
Great Grey Owl (Strix nebulosa)
As the largest owl in North America, the Great Grey Owl is relatively uncommon and rarely seen by humans. They can be found in dense coniferous forests and wooden bogs across the Northern Hemisphere. Although mainly a nocturnal hunter, it has also been observed hunting during dawn and dusk, mainly for mice but also occasionally small mammals and birds. Because of their graceful and silent hunting techniques and the rarity of sighting, the Great Grey Owl is well known as the “Phantom of the North.” The population dynamics of these owls relies heavily on the abundance of voles since 80-90% of their diet is comprised of small rodents, especially voles. Largely deserving of its name, the Great Grey Owl can have a wingspan of up to five feet!
Barred Owl (Strix varia)
Unlike most owls, the Barred Owl has large dark brown eyes and is one of the most vocal owls. Although they are mainly nocturnal, Barred Owl’s loud hooting, screaming and cackling can often be heard during the day. The belly feathers of some Barred Owls have been observed as pink: it is theorized that this coloration is a result of eating many crayfish similarly to how flamingos are pink because of large consumption of brine shrimp. Fairly common in southern swamps, Barred Owls habitat expanded into dense forests across northwest America around the turn of the 20th century. It is most commonly thought that this northwestern expansion was caused by human alteration to the landscape. In California, Oregon, Washington and British Columbia, the Barred Owls are invading the habitat and landscape of the Northern Spotted Owl, adding to the decline of this already threatened species.
Short-eared Owl (Asio flammeus)
Often well hidden, the Short-eared Owl hunts at night and on cloudy days, typically in an area that several Short-eared Owls share. Unlike many owls, these ground-nesters nest in a depression in the ground cushioned with short grasses. Short-eared Owls can be found in a variety of habitats such as marshes, forest clearings, grasslands, agricultural fields and tundra. Short-eared Owls are one of six owl species that reside outside of forested areas and have one of the most widespread distributions, residing on every continent besides Antarctica and Australia. Only about 15 inches in length on average, these little owls can travel large distances including over large bodies of water. The largest distance recorded was a migration of 1,200 miles!
Long-eared Owl (Asio otus)
The Long-eared Owl has a large range over the North American continent, however as a species that prefers dense forested areas and are excellent at camouflaging themselves, the Long-eared Owl is uncommonly seen by humans. They are strictly nocturnal, and like many owls, do not build their own nests. Instead, they reside in the nest of a magpie, crow or squirrel forcing the previous inhabitants to build a new nest elsewhere. The Long-eared Owl is occasionally mobbed by smaller birds, but even so it rarely attacks them and mainly feeds on rodents. Although usually a quieter owl, the hoot of a male can be heard up to 0.7 miles away!
Northern Pygmy Owl (Glaucidium californicum)
Northern Pygmy Owls are widespread in forested areas and can be found in a variety of tree species from blue oaks to conifers. As active hunters during the day, Northern Pygmy Owls have a large, diverse diet. They prefer to reside in abandoned woodpecker holes high up in trees, but can also be found nesting in debris at the bottom of trees. These owls are skilled hunters with an appetite for songbirds, and although they are quite small, they occasionally take prey up to three times their size! Mobs of songbirds can often be a good identifier for where a Northern Pygmy Owl may be hiding, since the songbirds use mobbing as a defensive tool against predation from the Pygmy Owl. Another good identifier of the Northern Pygmy Owl is the two yellow spots on the plumage on the back of their neck. It is theorized that these spots mislead a predator, such as a hawk or cat, into thinking the owl is watching them.
Northern Saw-whet Owl (Aegolius acadicus)
One of the smallest owls in the world, about seven inches in length, the Northern Saw-whet Owl resides in dense coniferous or mixed forests and wooded marshes, throughout the majority of Canada, the United States and parts of Mexico. Roosting in its nesting tree during the day, the Northern Saw-whet Owl hunts small rodents and large beetles during the night. Juvenile Northern Saw-whet Owls, looking like little puffs with eyes, are chocolate brown with tan bellies and a white triangular patch on the forehead. The coloration of the juveniles is vastly different from those of adults, and can easily be misidentified as separate species. After their first summer, around one year of age, juveniles will molt and gain the plumage of an adult Northern Saw-whet Owl. Another interesting characteristic of Northern Saw-whet Owl is that they will collect and store their prey. In the winter, when a cached rodent is frozen, the owl will sit on its prey to dethaw it before consumption.
A full list of references can be found here.