Our Feathered Mousetraps OWLS Our Feathered Mousetraps We will look at Iowa’s three common owls, a selection of visiting owls and owl adaptations which make them excellent feathered mousetraps.

Great Horned Owl Feather tufts Yellow eyes “Tiger of the Treetops” This Great Horned Owl with its piercing yellow eyes and sharp talons is known as the Tiger of the Tree Tops.

Aggressive 20 inches tall 5 foot wingspan Conifer woods This aggressive owl stands about 20” tall and has a 5’ wingspan. Listen for its hooting in deep woods, especially woods containing evergreen trees.

Defensive posture Stay away! When provoked owls may take on this defensive posture. By fluffing up its feathers and holding its wings out, the owl makes itself appear larger in order to scare off intruders.

Great Horned owlets Perhaps this owl was trying to protect her chicks after they had fallen out of the nest. Great Horned Owl chicks grow quickly and eat a large amount of food.

On the menu: We often call owls “mousetraps” because their diet is high in mice, but other menu items are rabbits……

On the menu: Thirteen-lined ground squirrels……..

On the menu: Snakes…….

On the menu: Songbirds………

On the menu: And an occasional skunk – making for a smelly Great Horned Owl! The owl’s poor sense of smell comes in handy here.

Barred Owl Quiet nature Brown eyes “Teddy Bear of the air” The Barred Owl with its dark brown eyes and quiet nature is known as the Teddy Bear of the Air.

Woods near rivers, ponds, or lakes Bars or stripes Camouflage 18 inches tall Woods near rivers, ponds, or lakes The Barred Owl, which is slightly smaller than the Great Horned Owl, stands about 18” tall. It gets its name from the horizontal and vertical bars on the front of the bird.

Cavity Nesters Like other owls, the Barred Owl is a cavity nester. That is, they nest in holes of standing dead trees.

Barred owlet Sometimes in a windstorm the tree may break at this weakened point, thus exposing a curious chick or two.

On the menu: Frogs Fish Crayfish Small mammals Songbirds Since the Barred owl is found in woodlands near water, they feed on frogs, fish, crayfish, small mammals and birds.

Swallow food whole Owls swallow their food whole without plucking feathers, fur or bones.

Head first The prey is swallowed head first……

Gulp! With successive gulps the prey – in this case a 13-lined ground squirrel – is slowly swallowed.

What’s next? The owl seems to be saying “You didn’t think I could eat the whole thing, did you?”

Owl Pellets Regurgitated 8 to 16 hours later Contains fur, feathers, and bones After 8 to 16 hours, the digestible material is consumed and the owl regurgitates the fur, feathers and bone in a pellet form. This action removes bacteria from the throat of the bird which, if left in place could grow and choke the bird.

The leg bone’s connected to the… This owl pellet can be taken apart to determine the owl’s diet.

Where in the world? Scientists often go to the woods to collect owl pellets for study.

Look at base of trees where owls have been roosting The best place to look for owl pellets is at the base of trees where owls have been roosting. Pellets show up well against the snow.

Eastern Screech Owl Aggressive 8 inches tall “Wild cat of the air” Don’t let the small size of this owl fool you! Know as the Wild cat of the Air this Screech Owl is very aggressive.

Found in small woodlots & orchards Two colors Gray-brown or red Found in small woodlots & orchards These owls come in two colors – grayish brown or red. The coloration has nothing to do with age, sex of the bird, or season, it’s just a genetic trait like our hair or eye color. Look for this species of owl in neighborhoods with large trees, small woodlots or orchards.

On the menu: Large insects Mice Small songbirds Reptiles Amphibians Prey includes large insects like grasshoppers, mice, small songbirds, reptiles and amphibians.

Iowa’s Three Common Owls The three owls we’ve just discussed are commonly found in Iowa. Do you remember their names?

Iowa’s Endangered Species Barn Owl Once common Monkey-like face DNR reintroduction attempted

Barn Owl chicks The Barn Owl is an endangered species in Iowa. Many years ago the Iowa DNR tried a reintroduction program but it was unsuccessful. The Barn owls reproduced but the Great Horned Owl thought baby Barn Owls were tasty and out competed the Barn Owl. Report any sitings of Barn Owls to the DNR or County Conservation Board.

Owl Visitors to Iowa Burrowing Owls Common in western Plains states Visits NW Iowa Nests underground Let’s take a look at some of the owls which might visit Iowa. First we’ll look at the Burrowing Owl. Normally found in the western Plains states it can sometimes be seen in NW Iowa. This species nests underground in prairie dog towns.

Owl Visitors to Iowa Long-eared Owl Long feather tufts Smaller than Great Horned Owl Found in Minnesota and Canada The Long-eared Owl is so-called because of its long feather tufts. These tufts are not ears at all, but simply feathers. This winter visitor is normally found in Minnesota and Canada.

Owl Visitors to Iowa Short-eared Owl Short feather tufts Often seen in daylight Found near fields, prairies, and marshes Can you see the short feather tufts on this owl? The Short-eared owl prefers the ground although it doesn’t enter holes like the Burrowing Owl. This winter visitor can often be seen in daylight near fields, prairies and marshes.

Owl Visitors to Iowa Saw-whet Owl Smaller than Screech Found in coniferous North woods Another winter visitor is the Saw-whet Owl. Although slightly smaller than the Screech Owl it is quite capable of catching a mouse or two for dinner. It is a very calm owl which is normally found in coniferous woods to the north.

Owl Visitors to Iowa Snowy Owl Found in Arctic Ventures south for food in winter Larger than Great Horned Owl The Snowy Owl ventures down from the Arctic in search of food. They have been spotted in Marshall County during many winters. Adult males are pure white. Adult females and young males have black spots.

Owl Visitors to Iowa What is it? Large white bird Feather tufts present Rare arctic phase of Great Horned Owl spotted in Marshall County At first glance, this appears to be another Snowy Owl, but look closely at its head. Can you see feather tufts? This is the rare arctic phase of the Great Horned Owl which was seen in Marshall County one winter.

Adaptations Excellent eyesight Large eyes set in facial disk Can see 10 times better at night Sometimes 100 times better! Owls have several adaptations that make them effective mousetraps. One is there excellent eyesight. Large eyes are set in the center of a circular facial disk. This acts as a funnel allowing owls to see 10x better than we can at night. In some species its 100x better! You could compare that to humans using a flashlight or street light to navigate in while owls could use the starlight alone.

Adaptations Excellent hearing Two slits on each side of head Handy feature on moonless nights What if it’s cloudy and there’s no starlight or moonlight to with which to navigate? It just so happens that owls also have excellent hearing. They don’t have external ear flaps like we do, but rather just slits in the side of their head. See the white patch between the two pencils in this photo? You’re looking right through the owl’s ear into the white stuffing on the inside of this taxidermy mount of the owl.

Adaptations Hawks have scale-covered legs Owls have feather-covered legs Feathers help to muffle sound In comparing the legs of hawks and owls, you’ll note the hawks have only a scaly covering while owls have feathers covering their feet. This feathery covering helps muffle sound which might give away an owl’s presence.

Adaptations Snowy Owl feet have an abundance of feathers Great leg warmers for cold arctic nights! In the case of the Snowy Owl’s feet the abundance of feathers helps protect its feet from the cold Arctic air as well.

Adaptations Close-up of outer primary flight feathers Comb-like serrations Creates silent flight A close-up look at the outer primary flight feathers show another interesting adaptation to quiet flight. The comb-like serrations break up the air flow over the wing to prevent whistling as the owl flies. A great way to sneak up on prey, don’t you think?

Predator: Friend or Foe? Historically, predators were persecuted Today, owls and hawks are protected Predators have an important role controlling prey populations Because owls are predators, they have often been persecuted. They have been shot and hung on fences as an example. Fortunately, owls and hawks are protected. Like other predators, they have an important role to play in controlling prey populations such as rodents.

Now that you have a greater awareness of owls, I hope you’ll realize that owls are an important natural resource which need our continued support.