By Lisa Wolling, Executive Directors
The weather has been so chilly since the New Year began, one can hardly imagine there are already “spring” babies being born. In our part of Texas, however, some babies have already arrived, in spite of the very cold weather.
Generally speaking, the larger a bird of prey is, the earlier in the year it will hatch. Therefore, in our area, bald eagles and great-horned owls commonly begin courting very late in the year, with nesting beginning in December/January.
For bald eagles, nest building may begin one to three months prior to eggs being laid. Eagles will often return to the same nest year after year, adding on to the previous nest, so older nests can become quite large (certainly large enough for a grown person to sit in). Peak egg-laying occurs in December, with hatching occurring primarily in January. The female eagle typically lays a clutch of 1 to 3 eggs, with the average clutch being two eggs. As with all birds of prey, eggs are laid days apart, and the eggs hatch in the same order they were laid. A second clutch may be laid if the first is lost. Incubation begins when the first egg is laid and usually lasts 34 to 36 days. Both the male and female incubate the eggs, but the female usually spends more time sitting while the male hunts. Once the eggs begin to hatch, the female’s presence at the nest becomes nearly constant. The male provides the majority of the food needed for his rapidly-growing family. Eventually, the female will take up her share of the hunting, but in the early days, all of her attention is given to the young at the nest.
Sometimes two or three chicks will survive (depending on availability of prey), but it is not uncommon for an older eaglet to kill a smaller one, especially if the older is a female (females are consistently larger than males in the raptor world). Should one chick attempt to kill its sibling, neither parent will intervene. Young birds grow rapidly, adding about one pound to their body weight every four or five days. At first, the prey is torn for them and fed in small pieces. Once they are old enough to hold their heads up (at about two weeks old), the stronger eaglet or eaglets often get fed more frequently. By three weeks of age, the eaglets are already about 12 inches tall and their feet and beaks are almost adult sized. By four to five weeks of age, the eaglets are able to stand and they begin tearing up their own food. By six weeks of age, the eaglets are almost as large as their parents, and by eight weeks the eaglets are beginning to stretch their wings in response to gusts of wind and may even be lifted off their feet for short periods. The young generally fledge (fly from the nest) by 11 to 12 weeks of age, but the adults continue to feed them for another 4 to 6 weeks while they learn to hunt. Once the young eagles are on their own, they migrate northward out of Texas, returning by the following September or October. Bald eagles do not gain their white head feathers until they are about four or five years old.
Great Horned Owls also begin courtship late in the year in preparation for breeding. They usually adopt a nest that was built by another species rather than construct their own nest, but they will also nest in tree cavities, dead snags, deserted buildings, human-made platforms, or even occasionally on the ground. Pairs may roost and hunt together near their future nest site for several months before laying eggs. Great Horned Owls sometimes line their nest with shreds of bark, leaves, downy feathers plucked from their own breast, fur or feathers from prey, or in some areas they add no lining at all. Nests deteriorate over the course of the breeding season, so they are seldom reused in subsequent years. Eggs are most commonly laid in late December or January, with a clutch of one to five eggs most common. Incubation of the eggs takes between 30 and 37 days. The female will incubate the eggs while her mate brings her food at the nest. As with eagles, eggs are laid days apart, and hatch in the same order they were laid. At hatching, the young’s eyes are closed and they are covered with a soft, white down. They grow rapidly, however. At first, prey is brought back to the nest and the parents will tear small pieces to feed to their young. As with many raptor species, older, larger chicks may push younger, weaker siblings from the nest. At about six weeks of age, the owlets begin “branching”, leaving the nest with short hops or jumps to nearby branches. By eight to nine weeks of age, the owlets will begin flying, although they continue to depend on their parents for several months. The owlets may stay with their parents until quite late in the year, sometimes as late as October. Great horned owls are very protective of their nests and young and will not hesitate to attack if they feel threatened.
To learn more about what we do and view pictures of many of the animals we assist, please visit our Facebook page at www.facebook.com/SavingTexasWildlife. Our educational visitor’s center is open the second Saturday of each month from 10 a.m. to 2 p.m., located at 29816 Dobbin Hufsmith Road, Magnolia, Texas, so the next open house date will be Saturday, February 10. Come on out and visit us, learn a little more about local wildlife, tour our visitor’s center, browse our small gift shop (also available online on our website), do some fun activities and a craft, and meet some of our non-releasable educational animals. There are many ways you can help support our efforts too. Details can be found at www.ftwl.org, and then click on “How to Help”.