Owls: Part One

Owl 180 Turn

Figure 1: A short-eared Owl turns his head 180°. Photo by Asle Baraa, http://yourshot.nationalgeographic.com/photos/3554325

Owls are an incredible group of birds. They have forward facing eyes that are fixed in their sockets and cannot move like ours. In order to look around they can swivel their heads 270 degrees (See figure 1). Some species are strictly nocturnal while other will hunt in the day. They have incredible hearing and use it to pinpoint where their prey is. Some have ear tufts which are not their ears, but are elongated feathers that are used in behaviors. Instead, owls have earholes called apertures. In many species, these are set with one higher than the other (See figure 2) to allow them to pinpoint the origin of the sound better by sensing differences in when the sound reaches their ears.

Owl Skull

Figure 2: Owl skull drawing showing earhole positions. Image courtesy of Eastern Kentucky University Department of Biological Sciences http://people.eku.edu/ritchisong/birdbrain2.html

Owls are silent fliers due to their feathers’ structure. The outermost flight feathers have a combed edge which suppresses noise (See figure 3), and the surfaces of the feathers absorb sound and appear “fluffier” than other those of other birds (See figure 4)(1).

Owl Feather

Figure 3: Combed edge of owl feather. Image courtesy of The Owl Pages, http://www.owlpages.com/image.php?image=articles-Owl+Physiology-Feathers-1

Owl Feather Comparison

Figure 4: Owl wing feather comparison showing differences in edge texture. Image courtesy of Chris Taylor’s Owl Physiology Study Activity, http://nides.bc.ca/Assignments/Animals/Owl.htm

Owls eat anything they can catch, from insects to mammals and even birds. Some like the Blakiston’s Fish Owl or Pel’s Fishing Owl catch fish and other aquatic prey. Large prey is torn into tiny pieces, but smaller prey is swallowed whole. Any indigestible parts are ejected as pellets (See figure 5). These pellets can be found on the ground and dissected for insight into an owl’s diet. I remember doing this in my 4th grade science class. It was one of the highlights of the year.

Owl Ejecting Pellet

Figure 5: Snowy owl ejecting a pellet after eating. Photo by James Cumming, http://yourshot.nationalgeographic.com/photos/2857222/

Owls may like to be quiet when hunting, but they have an incredible range of sounds. They will call to attract mates, communicate with their mate, call to chicks and hold territories. See next post for owl calls. They are territorial and roost alone or in pairs, but outside the breeding season, some like the Short-eared Owl and Long-eared Owl will roost in small flocks. When breeding, only females incubate, and it is the male’s job to feed her while she is on their eggs. Owls do not make nests like a robin or a house wren. The type of nest sites varies greatly among species, but they often take advantage of something that is already there. It could be an old nest from another bird, a tree hole, rock crevice, abandoned building, nest box and some nest on the ground. Many will collect soft things like leaves, feathers or even shred old pellets to cushion the eggs.

Nesting Screech

Figure 6a: Nesting Screech Owl chick. B. Fledging Photo courtesy of The Owl Foundation, http://www.theowlfoundation.ca/RescueInfo.htm

Fledging Screech

Figure 6b: Fledging Screech Owl. B. Fledging Photo courtesy of The Owl Foundation, http://www.theowlfoundation.ca/RescueInfo.htm

Usually incubation starts after the first egg is laid and chicks begin hatching in the same sequence. When first hatched, the chick is covered in a soft white natal down (See figure 6A). When the chick is close to fledging, this is replaced by a fluffy plumage that looks more like an adult bird (See figure 6B). After fledging, or leaving, the nest, the chicks will stay close to their parents and call for food. The time they spend with their parents is variable among species, but it can range from just a few weeks to a few months (1). What should you do if you find an owl chick? It all depends on how old the chick is. If the chick is a nestling (Figure 6A), then it is in the chick’s best interest to call a rehabilitator ASAP who can raise the chick for future release. Do not try to raise them yourself, and I know it’s counterintuitive, but do not feed or give water without instruction. Their throat anatomy is very different, and you can cause more harm than good. These chicks must be kept warm since they cannot thermoregulate themselves. If the chick is a fledging (Figure 6B), the chick most likely was trying to follow its parents around. The first thing to do is to get it off the ground out of reach of predators. Place it on a branch or ledge. It’s often just a problem that the chick couldn’t find a way to climb up off the ground. The parents will return to feed it soon. Remember, this is only good if it is a fledgling. If the chick is injured or a nestling, you need to contact a wildlife rehabilitator or your local humane society immediately (2). To find a rehabber in your area check these websites:

If you are in or near the St. Louis area call the World Bird Sanctuary  (636) 938-6193 or the Wild Bird Rehabilitation Center (314) 984-9116. Check out the next post for owl species in your area, owl events, links to some fantastic owl nest cameras, and how you can get involved in local owl conservation. Works Cited: 1 Konig, Claus, Friedhelm Weick, and An-Hendrick Becking. “Owls: An Overview.” Owls of the World.2nd ed. New Haven: Yale UP, 2008. 18-39. 2 “Finding Injured Raptors.” The Owl Foundation. The Owl Foundation. Web. 3 Dec. 2014. <http://www.theowlfoundation.ca/RescueInfo.htm>.

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