What nocturnal predator has huge eyes, a swiveling head, and attacks prey on silent wings? An owl! Many people, including myself, are obsessed with owls. It’s no secret why; their nighttime habits, regal appearance, and difficulty to find make them an intriguing challenge among nature lovers.
The Eastern Screech-Owl (Megascops asio) can be found throughout almost the entire central and eastern United States. The word “asio” means “horned owl,” referencing the distinctive tufts of feathers on their head. Look for them in parks, various kinds of wooded habitats, wetlands, riparian areas, and fields. When they roost during the day, they can be found in tree cavities, on branches, hiding in vegetation, or even resting on man-made structures. Their tolerance of urban and suburban areas makes them accessible to most people, even city-goers who only have access to small parks or wooded habitats. Screech-owls can look surprisingly similar to a dead snag on a tree by stretching themselves out when threatened to blend in with their environment. Their color, streaking, and ear tufts all help camouflage these sneaky birds.
Most field guides list only two color morphs of the Eastern Screech-Owl: red and gray. However, many people are not as familiar with the lesser known brown morph. This is not surprising since only eight percent of screech-owls across their range are classified as brown. Nobody is entirely sure how screech-owl color is genetically determined, and it does not seem to affect mating and reproduction. Different morphs will mate with each other and sometimes all the colors will be represented in a single clutch. Whether ghostly gray, fox red, or chocolate brown, stumbling upon an owl of any color variation is always a fun experience.
Screech-Owls are tiny hunters, topping out at less than nine inches in height and weighing around half a pound. After sunset, when they are most active, these owls take off from their daytime roost to catch a meal. Their massive eyes give them an advantage in the dark. In fact, owl eyes are so large that they cannot even move inside their eye sockets. Woodlands are their preferred hunting grounds, but forest edges, fields, and wetlands also make a great place for finding a nighttime snack. Their round facial disks focus sound towards their ears, helping them pinpoint prey. From a perch, they search for small rodents, bats, small or sometimes larger birds, insects, amphibians, reptiles, and even worms, scorpions, and crayfish. These owls are diverse hunters – one was observed hunting from a hole in the ice left by a fisherman! Once they spot their prey, they swoop down, snatch it with their talons, and swallow the unlucky victims in one bite. Their feet are special – two toes face forward and two face backward, making it easier to grab hold of squirmy critters. Bigger prey is usually taken back to a perch and eaten in little pieces.
I have heard many stories of runners or hikers frozen in fear when they hear the eerie tremolo of a ghost at night. As it turns out, that eerie ghost is really just a talkative screech-owl. They often give a “tremolo” or monotone trill for communication between pairs and among family groups. Another common song is the “whinny,” typically used for territory defense. The songs can frequently be heard given in tandem. Barks, hissing, soft hoots, and bill snaps are other sounds that these birds sometimes make. Just as their name suggests, they do give a harsh screech, especially when protecting young.
When breeding season rolls around, the males break out their singing and dancing skills. After singing to the female, the male continuously moves closer and closer. He then begins bobbing his head and body until the female takes notice. To make the display even fancier, the male sometimes gives his potential mate an enticing wink. When the female approves, they begin to bond by preening each other. Bonding is important because screech-owls generally mate for life. Nests are usually in tree cavities, but screech-owls are no stranger to using a nest box. Females lay and primarily incubate 2-6 stark white eggs. The young also appear white after they hatch. They soon develop more feathers but retain an adorable layer of grayish fuzz by the time they fledge.
I recently saw a brown morph roosting in a tree at a local park. It blended perfectly into the bark, making it almost impossible to discern from the cavity it was occupying. At the base of the tree, a small, dark lump lay on the ground. Owls regurgitate pellets, which encapsulate fur, bones, teeth, feathers and other indigestible parts of their prey. After a fascinating dissection, the skull of a Northern Short-tailed Shrew (Blarina brevicauda) was uncovered from this pellet. Finding an owl and dissecting its pellet is like taking a snapshot of its lifestyle. For those who know where to look, or are lucky enough to find one, spotting an owl is always a treat! Learning about the owls near you can be a fun and rewarding experience.