Short description of Owl Copulation:

The female goes into a sort of squat as the male edges toward her and as he places a foot low on her back with his wings partially outspread, she partially spreads her own and tilts her underside toward him. The male presses his cloacal opening close to hers and copulation commences, continuing for as short a time as 5 to 10 seconds to upward of 30 seconds.
The act of copulation is sometimes repeated within about five minutes but more often the two birds fly off immediately after the first, the female leading the way and the male close behind her. Copulation probably occurs numerous times over the next eight or ten nights.

First Hand Description of Owl Copulation:

We had chosen to begin our foray at Caumsett State Forest, on the Housatonic River. There the river channel has been broadened into a pleasure boating area called Lake Zoar. We were standing on the west shore, facing this area and a forested ridge about half a mile tip the east. Directly in front of us was a large open horseshoe of hemlock trees, about fifty feet deep and twenty feet wide, with the arch of the shoe toward the water and the two sides framing us. I heard a horned owl calling from the cliffs to the east. It was a very deep call and I assumed it to be a female. Half in fun, I tried to see if I could get it to fly to us. A squeal and a hoot, and the incredible happened-a huge dark shadow emerged from the mountains, sailed across a quarter mile of moonlit water, and landed in the cusp of the hemlock stand.
The owl began to go through one of the most bizarre sets of antics I have ever seen a wild animal perform. It bowed deeply over and over, it hooted repeatedly, often pausing, tilting its head to right and left and peering intently as though it were trying to find out if its hoots had produced the desired effect. Between hoots, as it peered, it emitted a startling medley of purrs and growls. Not quite prepared for anything like this, I thought I'd try the "pishing" sound so often used by birders to pull sparrows out of the bush. The owl instantly responded with a loud hair-raising squeal while spreading its wings and erecting its tufts to the fullest. I could imagine newspaper headlines about two birders collected the next day in the form of owl pellets.
Then, from a distant ridge to the southwest, we heard a higher-pitched hoot, and suddenly the gigantic silhouette of a female great horned owl was outlined against the western sky. The big bird landed in the left prong of the horseshoe not more than fifteen feet away from us. I now realized that the first owl must be a male.
By then all hell had broken loose. Boy and girl bird had been brought together by a human being, probably the first in history to become a marriage broker to owls. I was rewarded for my services with the spectacle of a two-month courtship ritual compressed into a few minutes.
The long period of antiphonal duetting, which serves first for sexual recognition, second to establish degree of submissiveness, and" finally to proclaim a consummated bond-was abbreviated to five minutes of intense vocal outbursts. These took place from the two separate perches, the birds remaining about fifty '' feet apart.
Next, the female flew cater-corner to the center right of the horseshoe, where she was joined by the male. Remaining a few inches apart, the pair spent several minutes bowing and scraping and praising each other with purring gurgles. Then they drew closer and went into three minutes or so of intense allopreening (mutual preening) accompanied by soft gurgly vocalizations. This entire second stage took another five minutes.
The birds then began an astonishing slow progression from limb to limb along the right edge of the horseshoe toward the cusp, around it, and then along the left side. At each of approximately six spots they stopped, faced each other, and rotated their bodies slowly on an imaginary vertical axis. At the same time they embraced each other by lifting their wings and overlapping them as if they were laying shingles, lifting and overlapping them again. The term "shingle dance" suggested itself on the spot.
This terpsichorean intimacy lasted another five minutes. Copulation then took place approximately halfway down the left side of the horseshoe. There was, of course, no chance for the precopulatory ritual feeding so often mentioned in the literature. The act itself was predictable. The female chose a limb about ten feet below the crown of a forty-foot hemlock and faced toward the water. The male had some difficulty mounting her since the branch directly overhead did not provide much clearance for the combined bulk of two massive birds. He was therefore obliged to go through quite a bit of squirming and vigorous clapping of his huge wings before he could establish a secure foothold on the back of his mate. At one moment as he flapped his wings, he struck a sleeping chickadee, which fled in mortal terror. It was not easy to time the duration of cloacal apposition; probably at did not last more than fifteen seconds. Note: In most birds, fertilization is accomplished by the passing of semen from one external opening (cloacal) into another; in copulation both openings are pressed against each other. Hence the term cloacal apposition.
This sequence would have been memorable enough had it been performed only once, but these lusty owls were on to a good thing and not about to let it go.
They separated, flew hack to their original perches, and repeated the entire ritual a secand time. Another fifteen minutes of hooting, allopreening, and shingle dancing. But no observers of owl antics have ever been more stunned than the author and his friend when, upon completion of their second performance, the two Lake Zoar owls separated and staged their amorous drama a third time! The writer recalls saying: "This is just to make sure I get the sequence right!"

Wasn't that just great !!??