By Mark Mlynek, Keeper
Included in 2023 Fall 
Trunkline
What is a zoo? If you ask people this question, you will likely hear responses such as, “a family-friendly place with lots of animals” or “a park-like setting with exhibits that have animals from all around the world.” The Louisville Zoo is that and more. Our Zoo is an arboretum full of various species of trees and flowers. Furthermore, it is a haven for wildlife.
A variety of wild mammals, birds, reptiles and amphibians call our Zoo home that are not considered official residents. Most of these animals stop by seasonally, either living on grounds during the warmer months of the year when food is plentiful or as a rest stop during their fall and spring migrations. However, some animals stay here all year long.
One special family of wild, full-time residents is a pair of red-shouldered hawks. Red-shouldered hawks are medium-sized raptors that are quite common in many parts of Kentucky including metro Louisville. They weigh between one and two pounds, with the females being larger than the males. Red-shouldered hawks’ preferred habitats are woodlands and swamps. The Louisville Zoo has plenty of trees, a swamp in the back and a variety of food sources for predators. So, it’s no surprise that our Zoo has been the pair’s ideal home for over twelve years. These wild hawks could not have chosen a better place to settle down and raise a family. Because they have made such a comfortable home here, the female has successfully hatched chicks every year on Zoo grounds.
Building a nest is not as simple as just throwing some sticks into a pile. Birds are very selective about what wood and leaves are used. The selection of branches and leaves are made based on needs for structure, comfort and insulation. Red-shouldered hawks will go out of their local area, if needed, to find a black cherry tree. This particular type of tree has a natural insect repellent within its leaves.
This pair takes nest security seriously. Each year, Zoo workers who have gotten too close may have received a warning smack on the head from the foot of a fly-by hawk. To protect guests, the Zoo puts up protective awnings under the nest during nesting seasons.
The female hawk will start sitting on her eggs in the middle of March. (Do you remember the 10 inches of snow we got on the first day of Spring in 2018? The female was in the nest, on her eggs, under that snow.) The incubation time for red-shouldered hawk eggs is about 33 days. During most of the years with us, the hatching of eggs was like clockwork, always near April 17. However, for the past two or three years, the schedule of laying the eggs and the hatching have occurred a week earlier. There may be two possible reasons for this: increasing age and body changes of the female, or a slight climate change in our environment with slightly warmer temperatures earlier than typically expected.
Every year, the female has hatched out three chicks, with the exception of one year with four chicks. While all the eggs have successfully hatched each year, our pair had two sad seasons when the chicks did not live very long. In the neighborhood around the Zoo, red-shouldered hawks are near the top of the food chain, but they are not at the very top; that spot belongs to the great horned owl! During two nesting seasons, a great horned owl raided the nest in the middle of the night, taking all the hawk chicks.
The roles of our female and male hawks are fairly set during nesting season. The female will tend to the nest while the male hunts and provides for the family. Occasionally, the male will give the female a break and temporarily take over nest duties while the female has a chance to get out, go for a flight and stretch her wings. After a successful hunt, the male will typically bring back small mammals and birds to the nest for food, but there has been a random offering of a snake or lizard. When the chicks are about 4 – 6 weeks old, they will be fully grown and have replaced all their white fuzz with feathers. After climbing out of the nest and walking onto the surrounding branches, they will begin testing their abilities by flapping their wings and building up their strength. After about 8 weeks old, the young ones will be in the air, learning to fly and hunt with their parents. Then, by the time autumn has come to the Zoo, the young will have left their parents to start a life on their own.
The exact age of our parent hawks will never be known. We do know they are at least 15 years old. With the maximum lifespan of a wild, red-shouldered hawk being around 20 years, that means that, unfortunately, our pair are in their twilight years. Once our pair has passed on, perhaps one of their offspring will move back into their parents’ territory and continue their legacy. Our pair have provided wonderful opportunities for Zoo workers and guests to observe the circles of life, as well as providing years of free pest control. Regardless of what happens, we are grateful to have been able to follow along on their journey and for everything they have taught us.