The Great Horned Owl

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.

The Unusual Fall Migration of the Tree Sparrow & January Feeder Survey Resuts

BIRD COLUMN FOR FEBRUARY 6, 2005

By Benjamin P. Burtt

TOPIC: The Unusual Fall Migration of the American Tree Sparrow as Shown by the Feeder Survey

INTRODUCTION

This column is divided into two sections

Section 1 discusses the migration of the tree sparrow which was discussed briefly in the bird column in the Post Standard in Syracuse on the above date.

Section 2 contains the Detailed Results for the January 2005 Feeder Survey

ANNOUNCEMENT: THE FEBRUARY FEEDER SURVEY STARTS TODAY AND ENDS SATURDAY

SECTION 1:
The Fall Migration of the American Tree Sparrow as Measured by the Feeder Survey

I have conducted a Feeder Survey in Central New York every winter for the past 47 years with the cooperation of readers of my Bird Column in the Post Standard. As the years have gone by we have learned some interesting things about the birds that spend the winter here.

During the first week of each month from October through May, readers watch their yard and count the number of birds of each species that are visible there. At the end of the week they send me a list of the species and the maximum number of each species they saw at one time during that week.

Using this information over the years we can get an idea of how the population of a given species changes over the years or even how it changes on the average through the winter from October through May.

Today, I want to tell you how I have learned something about the migration of the tree sparrow. Tree sparrows are present in Central NY from October through May, but they go far to the north in the summer to breed and then come back in the fall.

Of all the birds that are tallied on every feeder survey from October through May, it is the only one that does not breed here. It is listed on nearly half the reports in mid-winter.

It nests about 1000 miles north in the summer in the wet, brushy wastes of northern Canada. This area is north of the trees and extends as far north as there is any scrubby growth.

Figure 1: This is the tree sparrow. ( Courtesy of Kevin and Jay McGowan)

How do we identify it? It is the only rusty-capped sparrow that is abundant here in winter. It reminds us a bit of the chipping sparrow that also has a rusty cap and is a summer resident. However, we must remember that in the winter the chipping sparrow does NOT have a rusty cap. The top of its head at that time of year is brown with black streaks running from front to back.

In addition to its rusty cap, the tree sparrow has a dark spot in the middle of the breast and the chipping sparrow does not. On some tree sparrows that spot is not very conspicuous and this leads some observers to think it might be a chipping sparrow.

The bill of the tree sparrow is two toned, that is, the top is black and the bottom is yellow. While the chippies bill is entirely black in summer, it fades to a gray-brown in winter, but both parts of the bill are still the same color .

The tree sparrow’s nest

The nests in the far north are on the ground and hidden in dense tangles of shrubs. The tree sparrow might better be called the “brush sparrow” for it seldom spends time in trees.

Why is it called “tree” sparrow if it spends so little time in trees? The early settlers noticed that it bore a resemblance to the chestnut-capped tree sparrow of Europe and Asia which has a rusty cap, but otherwise resembles a house sparrow. A few of these European tree sparrows were released around St. Louis and you will find them in some of the field guides. In this country they are called Eurasian Tree Sparrows. Anyway, the early settlers gave it the name tree sparrow and the official name today is American Tree Sparrow.

The fall migration of the tree sparrow

This is where the feeder survey has provided some interesting information. The tree sparrow leaves that northern nesting area before September ends and starts a journey southward. A few appear here in Central New York in early October.


Figure 2 shows how the abundance of the tree sparrow changes during the winter here in Central New York. This chart is obtained from the Feeder Survey over the years.

Figure 2 In the chart, the number of tree sparrows per 100 reports is plotted on the vertical axis against the month on the horizontal axis. The number of birds for each month is the average of the counts for that month for the years from 1999 through 2003.

For example, The average of the January counts for each of those five years was 280 tree sparrows per 100 reports. For this January, 2005 it was 206. So this year the tally was a bit below the average for January.

Every year they leave their breeding grounds in the north in late September.
A few tree sparrows first appear here in early October. The numbers slowly increase here in Central New York and it takes 5 months for the numbers to reach a peak value. The numbers remain at a high level through February and March with the maximum count usually being in February.

In April, the numbers decrease as these birds start to leave for the north. By early May only a few remain, but all are gone by the end of that month.

The puzzling question is, why does it take so long for this fall migration?

Another bird that nests in the far north and migrates to the United States for the winter is the white-crowned sparrow. Its migration is more typical of the sparrow family.

The white-crowned sparrow, instead of making a leisurely migration, rushes along as do most birds and they all pass through here in October to go further south. We seldom see any during the rest of the winter. None were reported on the January survey just past.

In May the white-crowned sparrow migrates through our area on its way back to the north. This occurs in the first week of May during the last survey for the season..

I can only speculate as to why the tree sparrow migrates so slowly in the fall. It has a tiny bill and feeds on the very small seeds of grasses and weeds. Such weed seeds would not be available if the snow gets very deep. So perhaps it moves to the south only enough to find weeds that are not covered with snow.

The white-crowned sparrow is a larger bird and has a heavier bill that can crack larger seeds. I would think that it might go even more slowly than the tree sparrow since it would be able to eat tree seeds in addition to those on weeds.

Even if I can not suggest why the tree sparrow goes slowly, the Survey shows that it does. The slow migration is nothing new for in looking back over the 47 years of the feeder survey, I see the same trends.

I am a bit surprised that more people do not report tree sparrows, but I suspect that some people may be using only a hanging tubular feeder with short perches. Tree sparrows and juncos normally feed on the ground and they will not use such a feeder. In such a case they can only feed on spilled seed.

To attract those two species put out a fine seed such as cracked corn or white proso millet. Scatter it on the ground or on a large platform or tray-like feeder on a post.

SECTION 2
THE DETAILS OF THE JANUARY FEEDER SURVEY.

The observations for the January Feeder Survey were made by readers during the first week of January.

What birds were most abundant at feeders during the first week of January when we conducted the feeder survey? While geese and crows were more abundant than any other species reported, they were not at feeders. Starlings were in third place and only some of them visit feeders regularly.

The most abundant bird right at feeders was the goldfinch. There were 837 per 100 feeders. We always present the numbers per 100 feeders so that comparisons can be made with results in the past.

The goldfinch count this year is not quite as high as last years record tally, but is way above average. In mid-winter the goldfinch has been the most abundant species at feeders in recent years.

After the goldfinch came the mourning dove, house sparrow, chickadee and junco. There were large numbers of cardinals and house finches.

It is also fun to know what species are present at most feeders. As usual, just about everyone had chickadees. 95% of the feeders had at least one. Other birds that were present at over 80% of the feeders were white-breasted nuthatches, downy woodpeckers, mourning doves and juncos. Over half the feeders had blue jays, goldfinches, titmice and hairy woodpeckers. The tree sparrow was listed by almost half the people.

A total of sixty species was spotted. Of these, 48 were fairly common, that is they were seen by 2 or more observers. The other 12 species were each seen by only one person.

The typical feeder had 13 species. By that I mean that half of the observers had more than 13 and the other half had less than 13.

The shortest lists.

The shortest list came from the New Haven Elementary School fourth grade class taught by Norma Griffin, they had 15 goldfinches and 2 mourning doves. E. Randall of Clinton tallied 4 species. In Watertown, Susan Fonday listed 5. There were 6 on the lists of Dawn Franits of Syracuse, Marsha Smith of Dryden and Mrs. William Woernley of Homer.

Tallying 7 were David Bigsby of Syracuse, Eugenia Fish of Cortland and Bob and Shirley Rock of Oswego. Cynthia Wallace had 8 in Elbridge.

The longest lists

The longest list came from Ken Smith in Groton, he had 32 species. In Waterloo, Linda Quackenbush had 31. Tallying 27 were David Pardee of Bremerton and Steve Swensen of Baldwinsville. Ken Zoller had 26 in West Winfield. Listing 25 was John and Elizabeth Wallace.

There were 22 on the lists from Paul Radway of Pompey, Steve and Dorothy Hanzlik of Whitney Point and Matt Young of DeRuyter.

Finches from the northThere are many other northern species that come down here when food is scarce in Canada. This year there has been no appreciable movement of northern finches as far south as Central New York. The northernmost survey came from Peter and Linda Biesemeyer of Malone. They did list some northern species. They had 30 redpolls, 4 pine siskins and 10 evening grosbeaks.

The Rare BirdsBirds listed by only 1 person were bufflehead by Mrs. Dana Coye at Skaneateles, a kingfisher at New Woodstock, reported by William and Marilyn Fais. Estelle Hahn of Dewitt has had a screech owl roosting in a nest box. David Pardee reported a great blue heron and a hermit thrush near Brewerton. Judy Thurber at Liverpool was the only person to report Herring gulls and Great black-backed gulls. Matt Young had a rusty blackbird at DeRuyter. Ken Zoller reported black ducks and horned larks at West Winfield.

There was one yellow-throated vireo reported, but the person did not tell how the bird was identified. This bird is normally in South America in winter and I can find no records of one here in winter. When an unusual bird is listed, it is very helpful if you give me the field marks that you used to identify the bird.

Two people reported chipping sparrows, Remember, the chipping sparrow does not have a reddish cap in winter. Most winter reports turn out to be tree sparrows.

The total pictureHere is the list of all species reported. The first figure is the number of birds spotted per 100 reports and the one in parentheses is the number of reports out of 100 that listed the species.

If you divide the number of birds by the number of reports for a particular species you get the average number visiting a feeder. It is fun to compare this with your own tally for that species.

Great blue heron 1 (1); Canada goose 2,729 (34).

Ducks: black 2 (1); mallard 21 (5); bufflehead 8 (1);

Daytime birds of prey: northern harrier 2 (2); sharp-shinned hawk 14 (14); Cooper’s hawk 19 (19); redtail 23 (19); rough-legged hawk 2 (2); pheasant 7 (4); ruffed grouse 3 (3); turkey 43 (5).

Gulls: ring-billed 21 (5); herring 2 (1); black-backed 2 (1); rock dove 129 (10); mourning dove 736 (83); screech owl 1 (1); horned owl 3 (2); kingfisher 1 (1).

Woodpeckers: red-bellied 50 (40); downy 192 (84); hairy 78 (52); flicker 4 (4); pileated 4 (4); horned lark 1 (1); blue jay 247 (67); crow 2,018 (84); raven 11 (5); chickadee 516 (95); titmouse 148 (64); red-breasted nuthatch 44 (32); white-breasted nuthatch 143 (85); brown creeper 4 (4); Carolina wren 4 (4); bluebird 11 (2); hermit thrush 1 (1); robin 72 (7); cedar waxwing 133 (8); northern shrike 2 (2); starling 941 (35); cardinal 355 (82).

Sparrows: tree 206 (44); chipping 4 (2); song 4 (3); white-throated 48 (16); junco 434 (79); red-winged blackbird 4 (2); rusty blackbird 1 (1); grackle 4 (3); cowbird 64 (7); purple finch 109(17); house finch 310 (41); redpoll 134 (8); pine siskin 5 (2); goldfinch 857 (67); evening grosbeak 10(1); house sparrow 667 (44).

Announcement: The February Feeder Survey starts today, February 6