W. T. Munro Wildlife Branch, Victoria, B.C. R. C. Lincoln Fish and Wildlife, Penticton, B.C. R. W. Ritcey Fish and Wildlife, Kamloops, B.C.

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1 REESTABLISHING BURROWING OWLS - EXPERIENCES IN BRITISH COLUMBIA* W. T. Munro Wildlife Branch, Victoria, B.C. R. C. Lincoln Fish and Wildlife, Penticton, B.C. R. W. Ritcey Fish and Wildlife, Kamloops, B.C. Abstract The burrowing owl (Athene cunicularia) was nearly extirpated as a breeding species in British Columbia by the late 1970's. It was officially designated as an endangered species in the province in March, As part of a recovery plan, 17 burrowing owls in 1983 and 34 owls in 1984 were reintroduced to two sites. In 1983, a pair of owls with their nine unfledged young were brought in from Washington and released in the south Okanagan and 7 one-year-old captive-bred birds provided by the Owl Rehabilitation Research Foundation in Ontario were released near Douglas Lake. In 1984, 5 adult and 24 young unfledged owl s were introduced from Washington and 5 one-year-old birds were brought in from Ontario. Artificial burrows, temporary cages and food future plans were are described provided at both sites. Methods, observations, results, and The burrowing owl formerly occurred as a breeding species in the arid interior valleys from Kamloops south (Fig. 1). Howie (1980), in reviewing that status of the species, suggested the absolute number of birds was always small and now "...except for isolated, unsubstantiated reports, it seems to have been eliminated as a breeding species." The last authentic report of burrowing owls breeding in B.C. was the observation by Wayne Campbell of the Provincial Musuem of three young and two adults near Douglas Lake in August, Loss of habitat to agriculture, housing and a severe reduction of the badger and other burrowing rodents which supply nesting sites are generally considered the major cause of the disappearance of the burrowing owl. The species was designated under the Wildlife Act as endangered in British Columbia in March, Paper presented to the Annual Conference of the Western Association of Fish and Wildlife Agencies, Victoria, British Columbia. July, 1984.

2 \G OWL V V RANGE RANGE IN GODFREY (1966) WINTER RANGE RELEASE SITES 1. Nicola \C BREEDING 2. Okanagan Figure 1. Historic distribution of the burrowing owl in British Columbia (from Howie, 1980).

3 3. Following that designation, a number of discussions on possibilities and methods of reintroducing the species were held which culminated with an agreement among the Fish and Wildlife Branch, the Federation of B.C. Naturalists and the University of B.C. to support the preparation of an annotated bibliography of burrowing owls and a preliminary recovery plan for the species In British Columbia. That work was done by a graduate student at UBC under the guidance of Dr. Fred Bunnell. Funds were provided by the Fish and Wildlife Branch, UBC, and the World Wildlife Fund. Two reports resulted, a bibliography (Dunbar, 1982) and a recovery plan (Dunbar, 1983). On the basis of that work, the Fish and Wildlife Branch prepared a pilot program for reintroduction of the species 1n the spring of Two sources of birds were available to us, adult and young wild birds from Washington state and one-year-old captive-bred birds from the Owl Rehabilitation Research Foundation in Ontario. Therefore, we designed our program to make use of both sources of birds. Two separate sites for release were chosen, both within the historical breeding range of the species, and both with some kind of secure tenure. One was in the Okanagan and one was in the Nicola area (Fig. 1). The site In the Okanagan was on Canadian Wildlife Service property and the site in the Nicola was on the Douglas Lake Ranch. A number of artificial burrows were constructed for each site similar to those described by Collins and Landry (1977). Each consisted of a nest chamber measuring 30 on by 30 cm by 20 on and a 10 cm by 10 on tunnel about 2 m in length with a right-angle turn about 60 cm from the nest chamber. The artificial burrows were buried with a downward slant so that the next box was about 30 cm below ground level. In 1983, 13 boxes were placed in the Okanagan site and 15 in the Nicola site. We placed the 13 artificial burrows in the Okanagan site 1n three groups. Each group had a 2 1/2 m perching pole adjacent to it. A large 10 m by 4 m by 1.8 m flight cage made of stretched, soft, fine-mesh seine netting was constructed over three of the burrows and two 1 m perching poles were placed inside. An observation blind was constructed on a hill about 100 m away from the cage. A prescribed burn was conducted on a portion of the area to reduce old vegetation and encourage new growth. In early June, 1983, Fish and Wildlife staff joined Washington State Wildlife staff near Moses Lake to capture a wild burrowing owl family. A pair of adults known to be feeding young was captured by placing a live trap in the burrow entrance. The burrow was then dug out and nine young captured. The adult birds were heavily infested with fleas and were treated with flea powder by a veterinarian 1n the U.S. before being brought to B.C. The young birds were engorged with mice shortly after excavation. The two adults and their nine young were flown to the Okanagan and released in the holding pen on June 7, The owlets were placed directly In the nesting chamber, fed until satiated, and then the chamber was closed and covered with earth. Because of the flea problem, a "Vapona" no-pest strip was chopped up and put in perforated 35 mm film containers, one container being buried in each nest chamber in the cage. Each adult owl was held for a few moments near the burrow entrance to allow it to fix its vision on the

4 burrow entrance and was then released to enter the burrow on its own to join its young. Both adults emerged from the burrows within two hours of release. Throughout the capture, transportation and holding process, every possible effort was made to reduce stress on the owls. Such efforts included handling the birds as little as possible, keeping them in dark containers and not subjecting them to sudden noises. The owls were observed continually from the blind for the first seven days and then at least once per day thereafter. During that time, dead mice and voles were left in the cage. The adults were observed taking food into the burrows and after a few days, the young emerged and were fed by the female adul t outsl de the burrows. Very few attempts were made to escape. The enclosure was removed on June 16. The adults remained in the area and continued to feed the young with both food provided in diminishing amounts by us and food caught by themselves. Pellet examination showed that insects made up the bulk of the diet. The owls left the release site in mid July after the young had fledged and were not reported again in B.C. The burrows were opened on August 2 and a leg band from one of the young was found in the burrow normally used only by the adult female. It appeared that young had been eaten by one or both of the adults. We have no reason to suspect the other young did not survive. The expectation was that the young birds, if they survived, would return to breed in the Okanagan in We assumed the adults would return to Washington to breed. In 1984, 5 adult owls and 24 young were transplanted from Wahington to the Okanagan on May 30. Procedures were the same as those in Each of the three family groups was placed in its own large pen. In addition to voles and mice, dead day old poultry chicks were left as food. The cages were removed on June 13. About 50 arti fi ci al burrows were i nstal 1 ed from the release site south to the Canadian border. In 1983, we placed the 15 artificial burrows on the Nicola site loosely grouped in four locations. We anticipated that the groupings would allow sufficient foraging areas for at least three pairs of owls and their young. Late in summer, we placed five more burrows at the site of Campbell's 1979 summer observation. We built four holding cages of chicken wire and 5 cm by 5 cm framing. Each had dimensions of approximately 183 on on a side and in height. Hinged doors provided access and were fitted with small padlocks for security. When installed, the holding cages were inconspicuous from the main travelled road. In addition, a locked gate controlled by Douglas Lake Ranch protected the site from possible vandalism. Larry McKeever, Owl Rehabi1i tati on Research Foundati on, Vi neland, Ontario, delivered seven yearling owls on April 29. We put them in cages placed over burrows in four locations. Three cages held a male and female while a lone female occupied a fourth cage.

5 5. Our original Intention was to hold the birds until mid summer to allow them to mate or at least establish a strong affinity for the release site. Mr, McKeever feared that the birds would damage their flight feathers if held long in the confined cages and that they would be unable to survive in the wild with such a handicap. Consequently, we decided that after banding, all birds would be released except for one pair. When released (near noon, Kay 2, 1983), all five birds were able to fly strongly and one was followed for several hundred meters by a photographer. However, they remained in the vicinity of the release site throughout the afternoon and at 7:30 pm, two were at one burrow and one each at two other burrows. The remaining pair was fed two fresh mice or voles daily until their release on May 31. The pair remained at the burrow after the confining cage was dismantled, and by 7:30 pm, the male still remained. The following day, despite searching the general area, the owls could not be found. None was seen until June 30 when a pair was seen at one burrow. From then until August 31, birds or fresh signs were seen Intermittently at burrow entrances. There was an unconfirmed sighting of three burrowing owls approximately 1 km NE of the release site on August 14. In late July, a single owl was seen approximately 24 km away. Also an unconfirmed sighting was made on November 30, almost 30 km from the release site* During the first week of October, fresh pellets were collected from two burrows. Cursory examination of summer pellets showed that much of the diet was insect and that beetles were the most conmon of the insects found. We expected the owls to develop an attachment to the site and for any survivors to return to breed there in In 1984, five one-year-old owls were brought in from Ontario. One died shortly after transfer to the cages on the release site. One pair appeared to lay and Incubate eggs. The other two birds did not. As the birds did not appear to damage flight feathers they are being held in the pens until mid-summer to try to strengthen their attachment to the release site. In late July a further two one-year-olds and 9 young owl s will be received from Ontario, taken to the release site, held for a few weeks and then released. During the 1983 trip to Washington to collect the birds, we noticed that most nesting owls near pastures were on road right-of-ways or areas where there were no cattle. The soil was light, as 1t is in the Okanagan, and we assume cattle would readily collapse burrows. A number of collapsed burrows were seen even where there were no cattle. Thus we suspect that 1n light soi 1 s cattle may have extremely del iterious effects on burowing owl s in natural burrows. Additionally, it appeared that the owl s along the right-of-ways had dug their own burrows in the disturbed area. It appeared that if some disturbance allowed them to get through the root layer, they could finish the job. A fresh burrow was occupied, and we believe excavated, by one of the adult burrowing owls shortly before they left the release site. In this case, the surface vegetation was so sparse that there was no root zone where the excavation started. Unfortunately, where the root zone is sparse,.there is a greater likelihood of the burrow collapsing.

6 We believe the 1983 pilot program showed that birds could be introduced by two distinct methods and survive for at least a few months. Slight improvements on the techniques gained from our experience in 1983 should increase the chances of success 1n Although no birds released in 1983 were observed in 1984, we expect it was due in large part to the small number of birds released. With the large number released in 1984, we hope and expect to see some birds return to breed in It will be at least two or three years before we know 1f the program will probably mean the long-term establishment of the burrowing owl as an unendangered breeding species in B.C. Acknowledgements Many agencies, organizations and individuals contributed to this program. Special thanks must go to Kay and Larry McKeever of the Owl Rehabilitation Research Foundation who supplied the owls for the Nicola area and to the Washington State Department of Game for supplying the owls for the Okanagan area. Ron Friesz of that agency was particularly helpful. Mrs. Dianne Murphy looked after the owls at the Nicola site and her son Michael collected mice and voles for daily feeding. The World Wildlife Fund (Canada) provided financial support through the Federation of B.C. Naturalists for the 1i terature research and preparati on of recovery pians. The Habi tat Conservation Fund provided operational funds for the transplants. We would also like to thank the many Individuals within our agency and the individual naturalists who helped in a great variety of ways. Literature Cited Collins C. T. and R. E. Landry Artificial nest burrows for burrowing owls. N. Am. Bird Bander 2: Dunbar, D. L Annotated bibliography of burrowing owls. B.C. Fish and Wildl. Br. Unpub. ms. 24pp Preliminary recovery plan for burrowing owls in British Columbia. B.C. Fish and Wildl. Br. Unpub. ms. 26pp. Godfrey, W. E The birds of Canada. Nat. Museum of Canada Bull pp. Howie, R The burrowing owl in British Columbia. pp in Threatened species and habitats in British Columbia and the Yukon. (R. Stace-Smith, L. Johns and P. Joslin, Eds.). B.C. Ministry of Environment, Victoria.