BIRD COLUMN FOR FEBRUARY 20, 2005
By Benjamin P. Burtt
TOPIC: The Great Horned Owl, the first bird to nest in the Spring in Central New York does not make its own nest, but uses an old red-tailed hawk nest or a crow nest if one can be found. This owl will use also use a nesting platform if it is constructed to the correct specifications.
INTRODUCTION
This topic was covered in my newspaper column in the Post Standard in Syracuse on the above date.
This version here on my web site contains everything that was in the newspaper plus a lot of additional information for the reader who is interested in learning more about the great horned owl and how to build a nesting platform for it.
Signs of Spring
Here in the northeast we are ready for signs of spring. However, today It is cold and there is snow on the ground, and the only sign that spring is on the way is that daylight lasts longer than it did in December.
However, for the great horned owl, spring is well underway. Most birds nest later on, but these owls have already finished courtship, mating and are now laying eggs.
Starting in mid-January there was a lot of hooting. During courtship the male approaches his mate along a branch on which she is perched. He bows his head, leans over, fluffs up his feathers and then droops his wings with his tail pointing straight up. From this position he swells up his white bib and gives a long drawn out series of hoots.
The male then resumes his upright position and the female goes through a similar ritual. Later they face each other and rub beaks and then snap them with a clicking sound.
CAPTION: The great horned owl is the first Central New York bird to nest in the spring. Since we seldom see one close by, I am using this picture to show the bird’s huge size. This particular owl had been hit by a car three years ago and was under the care of wildlife rehabilitator Cynthia Page of Manlius. When its broken wings eventually healed, it was released. ( Courtesy of Cynthia Page).
They never make a nest of their own, but must find something they can use. In Central New York, they very often choose an old red-tailed hawk nest . It is a good choice for it is large and made of sturdy sticks. They must take what they can find and they sometimes use last year’s nest made by a crow or even a leaf nest made by a squirrel. They can use a hollow tree. One nest was in the crotch of a tree where three huge branches came together. There was no nesting material at all, but a single young owl was successfully raised there. That nest, of all places was in a tree in Oakwood Cemetery in Syracuse.
Once they have selected a site, they spend a great deal of time in the vicinity as the time for egg laying approaches. The female will even sit in the nest a lot before the eggs are laid.
These borrowed nests are not always in good condition. They sometimes fall apart from previous wear and tear and the effect of past storms. The eggs or young can be dumped to the ground prematurely
Two eggs are laid, but about a week apart starting about now. Incubation starts with the first egg and continues for about 35 days per egg.
One time I was inspecting a nest from the ground through my telescope and there was a mound of snow covering the nest. As I was about to take my eye from the scope, I saw the snow move and it appeared to shake itself. From under a coat of snow appeared the head of mother owl!
Two white downy young will hatch in mid-March. They will be the size of the chicks of domestic chickens.
They will be in the nest for over a month, during which time they need constant protection from the snow and low temperatures.
For many years in the 1950's and 60's I was studying great horned owls and red tailed hawks by banding their nestlings. If the banded bird was ever found, one could learn how long it lived and where it went. To do this I had to find active nests and climb to the nest at the appropriate time to put U.S. Fish and Wildlife bands on the young birds. .
Around the first of April, I would check known nests of red-tailed hawks to see if there was any activity around the nest they had used the previous year. If so, there would be hawk eggs in the nest and the female would be incubating.
Sometimes though, I would find that great horned owls had taken over the site a month before the hawks and half grown owls were in the nest about ready to be banded.
A day in the woods
In the Eaton area, Gerald Church would often find horned owl nests for me. When the young were the right age for banding, we would pick a day to do it when there was a blue sky and lots of sun. It was nice to be out in the woods in the early spring.
Here is one day I remember. Patches of snow were still present in shady spots on some of the hills. The nest was in an old beech and only about 40 feet up.
A sling shot was used to fire a lead weight over a branch. This weight carried a nylon fishing line. That line was used to pull up a clothes line which in turn was used to pull up a heavy manila rope over the branch and down to the ground. Gerry would tie himself to one end of the manila rope and the other was secured to my safety belt. With the aid of a pair of climbing spikes, I went up the tree while Gerry backed off through the woods keeping the rope tight.
There was a 3-week old horned owl in the nest and at this age it was still timid and easy to band. However, he puffed himself up in a somewhat threatening way to become a big ball of fluffy feathers. In the nest could be seen the remains of a rabbit and the bones of many rodents. I even found the leg of a racing pigeon with the band still on it from a club in Albany.
Another nest
A few days later, Church called to report that he had found another nest with young that were larger and almost adult size. I met the Churches early one morning and we went to that nest. This one was about 60 feet up in a maple tree and the two young were indeed fully feathered.
We tried to be quiet around the nest during the climb, for young owls frequently leave the nest on the slightest excuse at this age. Sure enough, when I was about 20 feet below the nest, one owl stepped to the edge, spread his wings and took his first jump into space.
The first flight is usually a long glide and the bird is unable to gain altitude. This young one was pretty strong and his wings were well developed. Consequently his glide was long and flat. Church went scrambling off through the woods behind the owl as I kept my eye on its path of flight. He found it perched uneasily in a small Hawthorne tree and brought it back to my pack basket at the base of the nesting tree.
To band the second one, I started up the tree again. My climb was continued as quietly as possible, but just as I tied myself in below the nest, the other one jumped out. Being younger, his wings were not as well able to support him and he took a rather steep glide to the leaf covered floor of the forest below.
He was easy to capture. Both owls were hauled up in the pack basket and I tied it to a branch. The youngsters were banded right in the basket. The first leg band was easy to put on, but the turmoil in the basket with two squirming full-grown owls that didn't want to be banded made the placing of the second band a bit more difficult. I wanted to be sure that the second leg that received a band was attached to the other owl!
Next I had to put the young in the nest and get to the ground without having them jump out again. Arranging one owl in each hand, I raised them above my head and placed them in the nest. They were held there with one hand over each one to keep them quiet. I was hidden below the nest (it's three feet across) so they couldn't see me as I slowly withdrew my hands.
They did not move so I climbed down quietly without shaking the tree. On the ground we quickly gathered all the equipment and moved off 100 yards where I removed the safety belt and spikes and packed all the equipment in the basket.
The young owls soon stood up to watch us, but showed no inclination to take to the air again--at least not that day. These were the last of ten owls that were banded that season. Some years later Church took up the banding of owls himself.
The first year for these owls is a dangerous time and most of those that I banded in the past were recovered in their first year. within 10 miles of the nest .
However, one of the three owls we banded that day (4/25/68) lived a very long time in the wild. When it was 19 years and 4 months old it was killed by a car one night as it flew low over a road near Morrisville. It was carrying a frog it had just captured! It was only a few miles from where it had been banded. At that time it was the oldest great horned owl in the banding records. Today, the record for a great horned owl banded as a nestling is a bit over 22 years.
More about the nests of the horned owlWhen it does find a place, it does very little to it. The adults will add a few feathers or grasses, but generally, they do nothing more to the nest than to make a slight hollow in the material there.
These old nests are often too small and in such poor shape that a young owl may fall out before it can fly. The edges may be made of soft vegetation and weak or rounded. If a young one gets too near the edge it will give way and the nestling crashes to the ground.
An owl nesting box
The great horned owl will nest in a man-made nesting box if it is constructed to the proper dimensions. Such a box is open at the top and would better be named a nesting platform.
For 12 years a great horned owl used a nesting platform in a tree back of my house. As shown, it is made from 2-by-4s and filled with straw, bark, sticks and hemlock boughs.
It is about two feet square with sides about 8 inches high made from two rectangles of 2-by-4s. The floor of the box is ½ inch plywood that is nailed on opposite sides to the under edge of the 2-by-4s. The sides of the floor reach to within 1/4 inch of the other two sides. This space prevents the nest box from collecting rain water.
Nesting materials
This tray-like box should be mounted from 20 to 40 feet up in a tree. It is filled with straw, sticks arranged in a circle and hemlock boughs to resemble a red-tailed hawk nest.
Insulation from the cold
These materials in the box provide some protection for the eggs and insulation from the cold. The materials used in a real hawk nest may be piled some 12 to 14 inches deep in the crotch of a large tree. These materials provide a great deal of insulation below the eggs.
Since my nesting platform was not that deep, special attention had to be paid to construct it so that the eggs laid in it would not lose heat through the bottom. The first model I designed was not well insulated and the owls that used it lost the eggs when the temperature was below zero for a few days.
After that experience I laid a 2 inch thick square of Styrofoam on the floor with a square of plywood on top of it. It somewhat resembled a sandwich with the Styrofoam between the wooden floor and the square of plywood laying on top of the foam. The nesting materials were then laid on the top piece of wood.
This nest is sturdy, for the four sides are made of 2x4s and a young owl can walk right to the edge with no danger of that side collapsing. Thus, the owls can remain in the nest until they are ready to fly. Such a nest in many cases is better than the old nests they sometimes have to use.
I had this platform in place for about 12 years and the owls used it 9 of those years. It was mounted in a tree on the edge of the woods about 500 feet behind the house. During the nesting season I watched the activity at the nest through a telescope that was placed just inside the big window that faced the nest.
Raccoons are attracted by owl eggs and I had to wrap the tree trunk with aluminum flashing after a loss of all the eggs one year.
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