Nest Observations

The Great Horned Owl Nest: Casual Observations Prior to Rescue
By Barb and Herb Draeger

• THE GREAT HORNED OWL NEST:The Owl Nest Has Collapsed
• THE GREAT HORNED OWL NEST: Follow Up Visits

March 1995 through May 13, 1995

General Observations of a Great Horned Owl
March 1995
Weather:
Temp: 41
Wind 15 to 25 MPH
Sky: clear
Time 11 a.m.
Near the entrance to a gravel pit not far from home there is a red-tailed hawk nest which had two chicks successfully fledge last year. A stately red oak holds the nest about 40 feet above a grassy hillside sloping into a small lake fed by the Mississippi River. The lake is about two acres and does not have a name, often I will refer to it as pond one, as there is a smaller pond (pond two) directly south east of pond one with a dividing road between that enters the gravel pit.

Herb and I received permission last year from the manager of the gravel pit to enter this area after signing an insurance release and agreeing to certain restrictions reguarding our presence on the property.

Herb and I inspected the nest from a reasonable distance and can see a pair of red-tailed hawks adding to the existing nest. The two are bonding, sitting side by side, preening each other, soaring in close circles and mutual feeding. Hope the two will mate soon, am curious to see how many chicks will fledge this year.

March 1995 Sunday
Time 11 a.m to noon
Weather
Temp: 34
Wind: 6 to 12 MPH
Sky: Partly Cloudy
Have discovered that the red-tailed hawks are gone and now in the nest is a great horned owl which is already obviously on a brood. The owl is down tight into the nest and seems to be sleeping. The great horned owl nest is the first found and it will be exciting to follow the progress of this nest.
It is common for great horned owls to take over hawk nests. Fortunately, the red-tailed hawks have perched about a half mile away and may build another nest. Evidence of which I have not been able to locate, but I am sure they will restart another nest as it is so early in their breeding season.

When brooding by the owl is complete, I will collect cast off pellets to see what food is preferred by this particular owl and her brood. Until there are clearly chicks on the nest, the area will remain undisturbed so as not to frighten the owl from the nest causing the eggs to die. Brooding season is the most dangerous time to approach any bird of prey nest as the parents will abandon it along with the eggs. Brooding requires constant temperatures to be maintained on the eggs which must be turned often to insure that the embryo will not stick to the side of the egg shell. This process is done by the parent for a full 30 to 35 days.

When the parent is absent from the nest the temperature is maintained by the down pulled from the breast of the bird and also by grasses piled around the eggs. The parent will not be absent from the nest for long periods of time, usually only for hunting she will leave the eggs for any length of time, and often the second parent is available to substitute sitting duties.

March 1995
Time: 12:45 p.m.
The road leading into the gravel pit is very busy at this time of the year as the crew is gearing up for the busy season. Many trucks and cars move down the road faster than they should. The owl seems to hide when vehicles come through the gate entry, but she remains alert. The displaced Red Tail Hawks have set up a temporary vantage sight on an Osprey platform located near pond two. There is no evidence of a nest being started at the platform.

5:26 p.m.
The owl was not at the nest upon first viewing, but she arrived within seven minutes. Her neck and head feathers are raised and she seems to have food, which she ate quickly. Actions in the nest are an occasional rocking back and forth. At one time she tucked her head down into the nest, the head came up as she starting rocking again. She ate once more, then with tail raised rocked down into the nest looking as if she's too big for the nest.

6:08 p.m.
The owl left the nest landing on a branch to the right, moving to a second branch and back to the nest with ruffled feathers, rocking back and forth she re-sat the eggs. At first the owl watched the fields around the area but did not hunt again. The owl moved her head in a clockwise motion as my husband walked up the road toward a better view. Even though the nest is over 1/2 of a mile away, the owl is fully able to see us on the road.

March 1995
Time: 5:30 to 6:15 p.m.
Wind: South 20 to 30 MPH
Temporarily the parent is off the nest, a small fluffy white head peeks curiously over the edge. There has been a hatch! The parent returned settling with the characteristic ruffled feathers and rocking. The owl saw the flash of the sun in the spotting scope lens we were using and "slid " her head side to side to clearly see the intruders. A gull swooped low diverting her attention briefly away.

April 1995
Time: 11:02 a.m. to noon
Weather:
Temp: 42
Wind: 30 MPH
Sky: Clear light clouds
The owl is tucked down deep into the nest with her back toward the wind to protect the chick seen a few days ago. Not much activity today.

April 1995
Time: 9:20 a.m.
Weather:
Temp: 34
Wind: 12 MPH West
Sky: Heavy overcast
The parent owl is sitting on the edge of the nest, Herb and I saw one chick, which is actively bobbing its head around. The chick moved from under the parents' wing protection, looking bigger than a few days ago.

There is some evidence of second stage down on the chick, the color is light tan with very little white and no sign of shafting on the feathers. The parent is asleep as the chick started to preen itself. We have not yet seen a second adult owl at the same time as the first one, but we believe the female is the one that stays close to the nest. The parent is awake now and pushed the baby with her wing. The chick doesn't seem cold or uncomfortable while out from under the parent.

9:40 a.m.
The baby is now tucking under the parent, who has her wings out some, there maybe another chick.

1 p.m.
Have stopped back at the owl nest after viewing other birds of prey nesting areas south of here several miles. The area is rich with wildlife of all kinds. Herb and I saw a second chick. This one is not as big, with feathers that are lighter in color than the first one we observed. One chick is obviously larger, a good guess would be that there could be a one to three day hatch difference.

The parent owl is asleep or trying to sleep. We can see clearly eyelashes on both baby chicks. The older is preening, rocking unsteadily as it pulls its beak down the feather plumbs.

3:35 to 4:10 p.m.
There is an adult eagle soaring over the area alerting the owl. These two birds of prey are enemies, as the great horned owl has been known to raid eagle nests. We again saw two chicks, one has its tail toward the road. The other shuffled around in the nest settling down close to the nest edge. The nest is not very large and they could fall out. The parent just calmly sits to one side lazily blinking her eyes. The oldest chick is fluttering a bit to cool itself. Both chicks have settled down for a nap.

April 1995
Time: 6:45 to 7 p.m.
Weather:
Temp: 52
Wind: NW 6 MPH
No parent is near the nest and the two owlets are securely in the nest. Have decided to walk in to the nest to retrieve pellets for Dr. Gary Duke at The Raptor Center, who has a great regard for these owls. The hike into the area below the nest will take us over the rolling hillside pockmarked with groundhog mounds and game trails lined with waist high weeds and grass.

7:35 p.m.
We retrieved one partial pellet plus some feathers nearby. Did not collect a semi-moist pellet that contained a bat carcass, am cautious as it may contain rabies germs. I turned it with a stick and was able to see the arm and fingers of one wing which was wrapped around the remains. The pellet was brown, leather-like and somewhat transparent. After spending some time below the nest, we decided to leave before total darkness enveloped the path. While driving out of the gravel pit, the adult owl swept straight down the road in front of the car, being trapped briefly in the beam of the headlights then escaping into the night.

April 1995
Time : 6 p.m.
Walked into nest area again, retrieved more pellets for examination. Seven white-tailed deer flashed their tails in alarm, bounding away as we approached.

8 to 8:20 p.m.
The oldest chick stood in the nest then jumped to a place slightly higher on the back right side, flapping its wings several times, turned around once then moved back down to the nest. The smaller chick stayed on the nest. The older chick again moved to the branch at the back right, followed by the small one. Both used their wings for balance, as a pushing match began. I think they are hungry.