Great Horned Owl
(Bubo virginianus)
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Brancher |
Fledgling |
Talon shot of Great Horned Owl |
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Great Horned Owls are among the largest and most aggressive of our North American owls, and they are the top avian predator in a wide range of ecosystems. Prey species include mammals, birds, and reptiles, and range from small rodents to animals as large as foxes, opossums, geese and herons. Because of the size and strength of their prey, young Horned Owls take much longer to develop and reach independence than small species such as kestrels and screech owls which subsist largely on such easy prey as insects and small rodents. To enable their offspring to have the entire summer to develop their hunting skills, and also to ensure the availability of prey during the peak of their nesting season, Great Horned Owls begin nesting in January. Thus, young Horned Owls are usually the first to be seen by wildlife rehabilitators. Because of their long dependence on their parents after fledging, it is extremely desirable to reunite or foster these young owls if at all possible, so that they can develop their hunting skills while still protected and supported by experienced adults.
These owls appear to be thriving in developed areas, and they often nest in suburban backyards and on golf courses. In Alabama, although they occasionally make use of ledges on rocky cliffs for their nests, they show a marked preference for nesting in the crowns of mature pines, usually occupying nests that were built by crows, hawks, or even squirrels. Since the owls do little or nothing to improve their nests, it is quite common for the nest to disintegrate, especially as the young put on weight and begin to move around. The mother bird stays on the nest guarding the young nestlings until they develop their thick coat of down and their eyes open. At about 3 to 4 weeks of age, the juveniles are able to feed themselves and keep themselves warm, and the female no longer stays on the nest. However, she assumes a watch post in a nearby tree, where she sits concealed in the canopy guarding her young from afar. Once you spot a nest, or a brancher, it is usually fairly easy to spot at least one adult on guard in a nearby pine tree.
Great Horned Owls readily accept the laundry basket nest (Case Histories 2, 3, 1, and 6) in cases where the original nest has been destroyed. If at all possible, the nest basket should be situated close to easy perching for the adults, or the edge of the basket should be reinforced with at least one large branch lashed firmly in place to provide perching for the adult.
It is routine for branchers to tumble to the ground, and to remain grounded for up to four weeks. The adults feed them on the ground, and the young birds stay concealed in low cover until they gain the strength and agility to hop and flap to perches above the ground.
Case History 4 describes one of several cases where grounded branchers refused to be placed in the trees, and insisted on staying on the ground, and even moved considerable distances on the ground. However, on many other occasions, branchers have accepted a boost back up into the trees, and have made their way up into the canopy when thus assisted (Case History 5). The determining factor may be the availability of smaller trees with plenty of low, interlocking branches that make it easy for juveniles to hop and flap their way up into the canopy. Golf courses have become common nest territories for Great Horned Owls in our area, and these specialized habitats present special challenges because of the large expanses of open ground. Many golf courses in our area have eliminated much of the understory, leaving only very tall trees with no low branches. It is not always easy to find a suitable thicket of inter-branching trees close to where the juvenile was originally found. Since young Great Horned Owls normally spend time on the ground, I have come to the conclusion that they do not need assistance if the parents are in the area and the golf course personnel are willing to keep and eye on the young birds.
In several cases, I have taken custody of a brancher that was in an unsafe location and kept it in a flight cage furnished with branches and other perches. As soon as the brancher could get up to the perch and stay there, it was returned to its family. An absence of one to two weeks made no difference, since another juvenile was still being tended.*
*text by Executive Director Anne Miller