Barn Owl Tyto alba
Case Histories
Case 1:
Nestling Barn Owls trapped in attic, relocated to nest box in nearby tree
Case 2: Older nestling
relocated to nest box from haven on front porch; orphaned nestling fostered to
same nest box
Case 3:
Brood of
orphaned Barn Owls fostered to adults whose own brood had all been killed
Case 4:
Older
nestling held for treatment, replaced by fostered nestling, later returned to
nest with fostered nestling and another sibling
Case 5: Older nestling
Barn Owls fledged from nest box with supplemental feeding
Development Photos
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Hatchlings |
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Young Nestlings |
Older Nestling |
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| Older nestlings almost ready to fledge | Fledgling |
Barn Owls belong to the family Tytonidae, while all the rest of the owls of North America belong to the family Strigidae. It is to be expected, then, that their behavior is quite different in some ways from other owls. For our purposes, the most notable difference is the extreme ferocity of the juveniles, which will be discussed in more detail below. Barn Owls are usually nocturnal hunters, and they specialize in hunting over open fields and pastures, using their long wings to cruise silently just above the grass while locating their prey primarily by their keen hearing. Their preferred prey is small rodents and other small mammals. In times of shortage, they are adaptable, and can make use of whatever prey is most abundant, including birds.
Barn Owls in the southern U.S. can raise as many as three annual broods. In our area the first brood is usually produced in April and May, another in the late summer (July and August), and a third in November. A single clutch usually contains 3 to 8 eggs, but as many as 12 eggs have been found in a single nest. Since the brood size is large, and the young hatch asynchronously, the difference in the size and age of the nestlings may be striking. As long as there is an ample food supply, I have not observed any problems caused by the great disparity in size among members of a brood.
While undisturbed juveniles can coexist peacefully, the
same cannot be said if the nest is disturbed. Nestling Barn Owls have powerful
talons, and they will attack aggressively if disturbed, even leaping forward
with talons outstretched to attack the intruder, meanwhile emitting a piercing
scream that is almost deafening. Perhaps the most difficult aspect of handling
these aggressive young birds is that once aroused, they attack anything, even
their own siblings. Thus it is necessary to keep the birds separate while they
are aroused, and allow them to gradually calm down before getting together
again. In a nest box or carrying box this is best done by putting each juvenile
in a different corner, so that they are out of striking distance of each other.
When introducing nestlings into a nest box, it is best to have a box that allows
enough space between the entrance and the back of the box so that each new bird
placed in the box can calm down before joining the others in the back of the
box, while those already there will not feel threatened by the close proximity
of the new bird. Usually, if handled gently, it only takes a few minutes for
the birds to mingle again as a single group. The young fledge in 55-60 days,
but remain dependent on the adults and return to the nest to roost for several
more weeks. Since Barn Owls often nest in old buildings, factories, barns, and
shooting stands, it is quite common to have to move young barn owls to a nest
box to avoid interference. These relocations are well tolerated if properly
done. My usual practice is to install the nest box as close as possible to the
original nest site, usually within 50 to 100 feet. However, I encountered a
case where a shooting stand was moved over a quarter of a mile before it was
discovered that it contained a brood of fledgling Barn Owls. In spite of the
extreme distance of the move, the adults were able to locate their brood and
continued to provide for them.[1]
[1] Marti, C. D., A. F. Poole and L. R. Bevier (2005). Barn Owl (Tyto alba). The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North American Online database: http://bna.birds.cornell.edu/BNA/account/Barn_Owl/.
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