In response to declining numbers of Barn Owls (Tyto alba) in the state, a management plan was implemented by the Nebraska Game and Parks Commission. The objectives of this plan are to: 1) Maintain existing active nest sites and establishment of a minimum of 75 new effective breeding pairs; 2) promote public awareness of raptors through restoration of Barn Owls (Lock 1980).
In order to achieve the stated objectives, two management techniques are being used. Artificial nest boxes are being placed in suitable structures in areas where Barn Owls still occur. Management plans call for placement of more than 35 nest boxes over the next 3 to 5 years. Nest box placement is an effective management tool in other states (Marti et al. 1979, Soucy 1980).
In an effort to increase Nebraska's breeding population, the release of captive bred birds in suitable areas where breeding is not known to be occurring is of prime importance. The Wachiska Audubon Society (WAS) Raptor Rehabilitation Program, Lincoln, was chosen to operate the captive breeding facility.
Since Barn Owls were already being housed at WAS rehabilitation facilities, the attempt to captive breed was initiated immediately. Proper state and federal permits were secured early in 1980.
Breeding stock consisted of 3 birds (1 female and 2 males) that were brought to the Rehabilitation facilities in July 1979 after being rescued from a collapsed nest at Medicine Creek Reservoir in Frontier County. The nestlings were raised by program volunteers and when fledging occurred were placed in a flight room at rehabilitation facilities. This room was adapted for use as a breeding chamber by cutting 2 small observation windows which were then covered with burlap to reduce disturbance to the Owls. In addition a special feeding hatch was cut near the chamber floor to enable volunteers to provide food without entering the chamber. A roost box was also built to provide extra cover. The Owls were kept in this room over the winter.
On 3 April 1980 a single egg was found on the floor in a corner of the chamber. A nest box was immediately placed in the chamber. The egg was removed and subsequent analysis by Commission personnel indicated a fertile egg. A second male in the breeding chamber was removed to allow the mated pair to nest undisturbed.
The first year mated siblings continued breeding activities as a second egg was laid in the nest box on 5 April. The clutch grew in size with eggs being laid every other day until a complete clutch of 7 eggs was being incubated on 20 April. During the first 2 weeks after the complete clutch was laid, the female would leave the nest box when it was approached. Towards the end of incubation the female was increasingly reluctant to leave the nest box (Figure 1).
Figure 1. Female owl with eggs and nestlings.
After 35 days of incubation, the first egg hatched on 10 May. Other eggs then hatched every other day until all 7 hatched. However, the 3 smallest Owls disappeared, the result of parental or sibling cannibalism. Large quantities of food were provided to prevent additional cannibalistic tendencies.
During the entire nesting period, the breeding chamber was closed to access to prevent disturbance. All feeding was done through the feeding hatch. Periodic visits checked on the condition of eggs and young and to remove excess food. This disturbance was done as quickly and quietly as possible.
On 1 July 1980 the 4 young Owls, 2 females and 2 males, were removed from the breeding chamber and placed in modified nest box located in an old wooden barn, northeast of Lincoln. Barn Owls had nested in 1977 approximately 800 meters (.5 mile) to the west (Lock 1978) and structures suitable for placement of nest boxes were available in the general area. The nest box was altered by placing wooden slats over the entrance to prevent premature fledging. A 7.5 centimeter (cm) (3") gap was left at one side to allow food to be placed in the box. After a week in the box, all 4 Owls escaped. Food was left in the barn for an additional 1.5 weeks during which 2 of the Owls were seen on several occasions. The hacking procedure was considered successful.
On the same date that the 4 Owls were placed in the nest box, 4 additional Barn Owls less than a week old were picked up at the Raymond Grain Elevator after their nest was destroyed. These Owls were placed with the pair of captive adult Owls which had already successfully raised young. The adult Owls accepted the young immediately and a sudden change in the size of young did not disrupt the breeding pair. They were much more effective parents than human volunteers and successfully raised the nestling Owls.
The fostered Barn Owls left the nest box at about 7.5 weeks. Three of the young Owls, 1 female and 2 males, were then placed into a nest box in an old barn southeast of Walton. The older female was kept for captive breeding. The nest box was modified by fastening a 60 x 60 x 90 cm (2' x 2' x 3') wire enclosure on the front of the box. This gave the Owls a chance to come out of the box to acclimate to the barn's environment before fledging. The 3 Owls were banded and placed in the nest box on 15 August. The wire enclosure was removed one week later but feeding continued. One Owl left the box the first night following removal of the wire enclosure and was seen flying near the barn. On the second night, a Barn Owl was observed near a wooded creek bottom north of the barn, while the two other Owls were in the barn where the nest box was located. Food was left for the Owls in the barn and was still being utilized at this stage of the release. At the end of the week following fledging, food was no longer left as the Owls had stopped utilizing it. This release was also considered successful.
Barn Owls have been successfully bred in captivity (Maestrelli 1973) but this is the first known captive breeding of raptors in Nebraska. This effort will continue as a special breeding chamber was constructed during the summer of 1980. It is a two chamber, chain link fence and wood structure built utilizing plans modified from McKeever (1979). Financing for the breeding chamber was supplied by the Nebraska Game and Parks Commission, Wachiska Audubon Society, and the Audubon Society of Omaha. The facility was built by rehabilitation program volunteers on land donated by Walter Bagley, Lincoln. This project has benefited from the help of many volunteers who donated considerable time and effort to assist in active management of a raptor species with a declining population in the state.
Currently, 3 pairs of Barn Owls are on hand for the 1981 breeding season. Birds have been paired to prevent sibling inbreeding and it is hoped the new pairings will be successful. Results will be reported in a subsequent paper.
Lock, R.A. 1978. A second great-gray owl record from Nebraska, and other recent owl records. Nebraska Bird Review 46(1): 16.
_____. 1980. Barn owl management plan. Nebraska Game and Parks Commission. 4 pp. Maestrelli, J.R. 1973. Propagation of barn owls in captivity. Auk 90(2): 426-428.
Marti, C.D., P.W. Wagner, and K.W. Denne. 1979. Nest boxes for the management of barn owls. Wildlife Society Bulletin 7(3): 145-148.
McKeever, K. 1979. Care and rehabilitation of injured owls. W.F. Rannie, Ontario, Canada. 112 pp.
Soucy, L. 1980. A study of the barn owl in New Jersey. In: Proceedings, 1980 Annual Meeting, Raptor Research Fountain. (Abstract only).Betsy Hancock and Jim Ducey, Wachiska Audubon Raptor Rehabilitation Program; Ross Lock, Nebraska Game and Parks Commission. June 1981. Captive breeding of ban owls in Nebraska - initial efforts. Nebraska Bird Review 49(2): 31-33.