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Blog written by: Kelsey Feighner

Owls have fascinated humans for hundreds of years. They used to be seen as an omen, often a bad one, foretelling death or misfortune. They gained a place in popular culture, often depicting a wise, old character that gives advice, particularly in children’s movies and books. More recently, owls have become quite noticeable in the Harry Potter books and movies, used by wizards to carry mail and packages.

In the natural world, owls are amazing birds that have numerous special adaptations that make them excellent hunters of the night. One of those adaptations is the distinctive facial disc of concave feathers that many owls sport. This special feature helps funnel the sound that comes towards them and direct it more accurately to their ears, allowing them to hear the noises of their prey better. Another cool adaptation that helps owls hear is their asymmetrical ears.  You cannot see owl ears easily – their ears are simply slits in the side of their heads. However, one ear is set higher up on the skull than the other ear. This gives them the ability to pinpoint exactly where a sound is coming from, even if their prey is buried beneath bedding or snow.

Like most birds of prey, owls also have excellent eyesight that allows them to quickly spot moving prey. Because many owls are active during the night, their eyes are specially adapted to see well in low-light conditions. Even so, they are still able to see as well or better than humans even during the daytime. Another characteristic that is commonly known about owls is the amazing degree of rotation they can achieve with their neck. While they cannot turn their heads around a full 360 degrees as some people think, they can turn it up to 270 degrees. Why can they do this? Humans can move our eyeballs without moving our head, in order to see to either side of us – called peripheral vision. Owls can’t move their eyeballs like we can, so they must be able to rotate their entire head in order to look to either side or behind them.

However, that head rotation is something humans definitely can’t do – if we tried turning our head around as far as an owl could, we would tear the big arteries in our neck! So how can owls do this? A study was recently conducted to find the answer to this question. The researchers found that owl neck arteries don’t go through every vertebra like they do on humans, and the spaces where they do go through are wider to avoid the bone damaging the arteries. They also discovered that owl arteries widen out into little reservoirs at the base of the head that keep the owl from losing consciousness from lack of blood to the brain when its head is rotated.

If you live in the country, or have walked past some trees at night, perhaps you’ve seen an owl in the wild before. Or maybe heard one? Do you know what kind of owl you spotted? Michigan has three common owls, as well as some less common species and one endangered species.

DSC03026  Starry and GHO in outdoor cg feb 2010  DSC03135

Common Owls of Michigan – Great Horned, Eastern Screech, and Barred

Great Horned Owls are the ones most commonly shown in popular culture. Some movies that you might recognize that feature Great Horned Owls…Bambi, Winnie the Pooh, and The Fox and the Hound. GHOs are most easily identified by their large size (up to two feet in length and 5.5 pounds) and their prominent ear tufts or “horns”. Remember, you can’t see owl ears easily, so those aren’t the actual ears you’re seeing. They’re just tufts of feathers meant for display and camouflage. GHOs also have yellow eyes and gray-brown mottled feathers. GHOs are a top predator in their ecosystem and will hunt many types of small mammals (including skunks) and even hunt other birds of prey. They make a characteristic “hoo-HOO-hoo-hoo” sound, among other noises. They are found in many types of habitats, but most often in wooded and agriculture areas. They are found in Michigan all year round.

Eastern Screech Owls are small and sometimes even mistaken for chicks! These little owls only reach from 6-10 inches long, and average from a quarter to half a pound. They are usually gray, but sometimes can be reddish-brown, both have yellow eyes. These owls also have ear tufts on top of their head. Their coloring and small size gives them excellent camouflage in tree perches and they will spend the daytime hiding in small nooks and crannies in trees. They obviously would prefer a nice tree hollow, but these owls are found in a wide range of habitats like GHOs, and also take well to human-built hiding places, such as nest boxes and sometimes even mailboxes or newspaper boxes! Your best bet for detecting a screech owl is to listen for their distinctive trill, or the sound for which their named, a screech. Their prey consists of mainly small mammals, small songbirds, and even a number of invertebrates. Screech owls are also found year round in Michigan.

Barred Owls are less well-known than the other birds in this group, mostly due to their common location being in old-growth, mature forests and swampy areas, away from human activities. They are a medium to large sized owl, averaging about a foot and a half in length. They have mottled brown and white coloring, with brown vertical stripes on a white underbelly. Their eyes are their most striking feature, completely dark brown or black. Like barn owls, they have a rounded head with no ear tufts. Barred owls tend to stay in one area and do not stray far from their territory unless threatened by the presence of a Great Horned owl, the most serious predator of the Barred Owl. Barred Owls, like the others, will eat small mammals and birds, as well as amphibians, reptiles, and invertebrates. They will also sometimes catch fish. Barred owls have a hooting call (among other sounds) that is described as sounding like “Who cooks for you?” They are also found year round in Michigan.

Saw whet owl Jan 2011  Picture 412  Barn owl picture

Less Common Owls of Michigan – Saw-whet, Snowy, Long-eared, and Barn

Saw-whet owls are similar in size to Eastern Screech owls, but a bit smaller, staying around 7-8 inches long. They have no ear tufts, yellow eyes, and a mottled brown and white body, with a white face outlined in brown. Saw-whet owls are found in forested areas and nests in tree cavities. They will also sometimes use nesting boxes like Eastern Screeches. They will sometimes hunt small songbirds and insects, but mostly hunt small mammals, especially mice. Their call is a series of whistle toots, sounding rather like a recorder. Saw-whet owls are found in Michigan year round, but are less common than Eastern Screech owls.

Snowy owls are one of the most easily-recognized owls, even by non-bird lovers. They are large, about the same size as a Great Horned Owl. They are mostly white with varying amounts of brown or black (females have more dark markings than males). Snowy owls spend their summers in the Arctic, but winter further south, through much of Canada and the upper US. These owls hunt mostly small mammals, but will also eat ptarmigan and waterfowl. They are one of the rare owl species that are diurnal – active during the day.

Long-eared owls are similar in coloring to Great Horned Owls, with gray-brown mottled feathers. They are smaller and thinner than GHOs, though, with longer ear tufts that are closer together. Long-eared owls hunt almost exclusively at night and are rarely seen. They are found in temperate forests, and hunt small mammals. Their call is a series of even, low hoots, around 2-4 seconds apart. They are found in Michigan year-round.  They are considered a threatened species in Michigan.

Barn Owls are another species that are very well known due to their striking appearance and widespread range. They are starting to become less common though, due to habitat loss. These owls are medium-sized, with a long body, and a distinctive heart-shaped face. They are typically 12-15 inches long. Barn owls typically have pale coloring, gray and brown on their back, with white underneath. They tend to have some spotting on the chest, especially in females. Unlike Great Horneds and Screeches, they do not have ear tufts. Barn owls are often found nesting in cavities like tree hollows, or human structures like silos and barns (hence the name). They hunt small mammals and occasionally birds, flying over open land. Barn owls have a cry that’s more of a scream than anything and definitely lends to the creepy image they already get from appearing ghost-like when they fly in the middle of the night. Despite this unsettling image though, these owls are useful (like many owls and birds of prey) to have around to help control the populations of common pests such as rats and mice. Barn owls are found year round in Lower Michigan, but as mentioned, are becoming a bit less common due to loss of habitat. They were thought to be extinct from Michigan until one was successfully rehabilitated and released in 2012. (Blandford Nature Center)  Before that Barn Owl was found, the last pair of breeding barn owls was seen in the state in 1983 with the last single Barn Owl seen in 2000.

DSC03143 Chloe: Sadly, Chloe passed away on Thursday, February 13, 2013

Short-eared Owl: Endangered

Short-eared owls are a medium-sized owl with mostly mottled brown feathers. They have a round head with no ear tufts and yellow eyes. They hunt mostly small mammals and have a different rare trait in owls – they are crepuscular, which means they hunt mostly at dawn and dusk. These owls are actually quite widespread throughout the world, and are found in most of North America, as well as the lower part of South America. However, they are endangered in Michigan because the habitat they’re found in, grasslands, are endangered. Lower Michigan once had many types of grassland, which were converted into agriculture land as humans settled there. Prairies and grasslands are now one of the most endangered habitats in Michigan, and the animals found in them are also endangered or extinct in the state. However, Wildside is lucky enough to have one of these rare owls as an education animal! Chloe came to us from southeast Michigan after suffering wing injury that rendered her non-releasable.

If you’d like the chance to see our education owl, Starry, the Great Horned Owl, feel free to join us at Woldumar Nature Center on Saturday, February 16th, at 5 pm, for the Owl Prowl! The event will include crafts and owl pellet dissection, as well as Wildside’s presentation at 6 p.m.  Afterward, participants can go on a night hike on the trails to listen for owls. Check out http://www.woldumar.org/programs.php?program=community for more information!

If you’re interested in reading further about birds, owls, or hearing the calls from these owls, check out our references for more great information!

References:

Vision & Hearing: http://www.owlpages.com/

Head Rotation: http://www.npr.org/blogs/health/2013/01/31/170758750/how-owls-spin-their-heads-without-tearing-arteries

Species Characteristics: http://www.allaboutbirds.org/

Barn Owl photo

File Photo: Barn Owl. By Phil Haynes [CC-BY-SA-2.0 (http://creativecommons.org/licenses/by-sa/2.0)%5D, via Wikimedia Commons

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