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Story and Photos by Brian Gosewisch
As a professional wildlife photographer and an avid birder, one of my favorite subjects is the great horned owl. I jump at every chance to encounter one of these magnificent birds, and every spring you will probably find me up a tree or in a blind studying and photographing the owls.
Living in Missouri, we are blessed with a healthy population of great horneds. From the mixed hardwoods in the south to the open farmlands in the north, great horned owls have proven to be adaptable in our state.
Courting and Nesting
One of the earliest birds to nest, courtship for the great horned owl starts in late fall, and by late January, the females will be sitting on the nest. Great horneds do not make their own nests; instead they prefer to take over existing nests that were made by hawks or crows and will on rare occasion use hollow trees as well.
Females will usually sit and incubate the eggs for about a month, and during that time the males are never far away. If you have not found a nest yet, go out and listen for the calls between males and females. Albeit less during the incubation period, they vocalize throughout the entire nesting season including, at times, during daylight hours.
If you approach a nest with a female inside, listen for the aggravated calls of the male, which has probably flown a safe distance away. If the male has flown, then the female knows that you are there, and she will not make a sound or even move. Females are very tentative when sitting on the eggs, and unlike other owls or hawks, they will allow you to approach very closely.
Remember to keep your distance and use binoculars for viewing. The closer you get to her, the more undue stress you put on her. Keep in mind that her only job for the next thirty days is to incubate her eggs. Her eating habits and everything else is in limbo during this time, therefore undue stress is unwelcome.
Hatching and Newborn
Once the eggs hatch in late March or April, you will notice what looks to be a surplus of food lying around the edge of the nest, from rabbits and mice to reptiles and even other birds. I have noticed this with almost all of the owl nests that I have documented over the years. This indicates three things to me: that there is plenty of prey, that the adults are capable of hunting it, and that the young are going to have the best possible start in life.
When the babies in the nest are between one and five days old, they are at their most vulnerable state. It is no coincidence that this is also when the parents are the most aggressive. If you mistakenly spook a mother away from the young, she will not go far. If the parents feel threatened you will see them chattering their beaks together rapidly, puffing their feathers, or in some instances, attacking. If the parents are showing any signs of aggression, leave immediately. Every time you disrupt a nest, especially in the daytime, you expose the young to other predators, and you also expose the adults to natural enemies like crows and jays.
Great horned owls have amazing camouflage, which makes them almost impossible to see. But when they are flushed, they are vulnerable. I have never seen a crow pass up a chance to harass an owl once they have spotted one, and if you have one crow, pretty soon you will have five or more. Fortunately, though, for the owl they are only an annoyance, not a threat.
Back at the nest you will find the female sitting with the young almost non-stop for the first week or so, and the male will be doing most of the hunting. As the babies get older, the parents spend less and less time at the nest, but they are never far away. The adults instinctively know when the babies reach a certain age and become restless, it does neither one of them any good to hang around the nest. Owls are naturally shy and secretive, and this might be a survival instinct to avoid any commotion that would draw attention and to help keep the nest visibility to a minimum. By this time, both parents are bringing food to the nest, and you can listen for the young owls’ begging calls, which last all the way through summer.
Around 25 days or older you should look for what can only be described as playtime. The young owls are getting restless, stretching and flapping their wings and hopping around the nest like it’s on fire.
One of my favorite memories of this playtime was a 31-day-old juvenile in a nest by itself. The nest was many years old and well built. Usually by the end of the nesting period, the nests are so worn down that it is sometimes hard to even identify them. This nest was large and still had a definite bowl in the middle. The young owl was jumping from one side of the bowl to the other and then turned around to do it over and over. Sometimes it would stretch out its wings and other times it would not. Although this did seem like playing, the owl was actually learning valuable skills such as balance and distance as well as gaining confidence to stick its first landing.
It has been my experience that an owl raised alone will generally leave the nest four to five days earlier than a nest with multiple owls in it. If conditions are good, such as food, habitat, etc., a single owl will leave the nest by around 34 days old. And multiples leave around 38 days. Many things could affect this number: a shortage of food supplies, overly cold winter, one parent dying, or even human presence. If everything goes well, the young owls will start branching out and soon be flying around just like the adults; however, they will stay close to home and their parents due to their continued reliance on them for food.
By next spring, the young owls will be on their own and forced to find their own way. Great horned owls are resilient and seem to thrive under many different situations. It is no wonder that these magical and sometimes mysterious birds are at the top of the food chain.