Burrowing Owl
The Burrowing Owl’s grassland habitat is being lost to agriculture and urban development.
Ministry of Environment, Lands and Parks What is their status? modification, pesticide use, traffic lthough information on the histori- mortality and related factors. Recent cal occurrence of Burrowing Owls in declines in eastern Saskatchewan and British Columbia is limited, we in Manitoba, where it may now be Why are Burrowing Owls Aknow there were several small extinct, are particularly alarming. As a at risk? nesting colonies present in the result of these trends, the owl’s national his diminutive owl has a very Okanagan and Thompson valleys from status was upgraded from Threatened restricted distribution and small 1900 to 1928. Numbers dwindled after to Endangered by the Committee on population in British Columbia. The that, with only four nesting sites being the Status of Endangered Wildlife in T overall abundance of Burrowing recorded between 1928 and 1980, at Canada () in 1996. Owls is limited by the availability of suit- which time they were thought to be The Burrowing Owl is widely distrib- able habitat. The grasslands in which extirpated as a breeding species in the uted outside of Canada, occurring in all they live are restricted to the dry valley province. Historical nesting areas states west of the Mississippi, in Florida, bottoms of the Southern Interior and include Osoyoos, Oliver, Penticton, and south into Mexico, Central America comprise less than one percent of the White Lake, lower Similkameen Valley, and South America. Populations have area of the province. This already small Coldstream, Vernon Commonage, declined in many of these areas due to area of natural grassland is being further Okanagan Landing, Knutsford, Savona, the loss or alteration of habitat. diminished by expanding towns, inten- Kamloops and Douglas Lake. As well, sive agriculture and urbanisation, esp- one or two pairs nested on Lulu Island in What do they look like? ecially in the Okanagan Valley and the the Fraser Delta during most years ommonly seen perching on the Thompson-Nicola region. from 1939 to ground or on fenceposts, the often In addition to causing habitat 1976, and birds comical-looking Burrowing Owl loss, human activities have also may still be nest- C (Athene cunicularia) has been contributed indirectly to the ing in that area. aptly described as a short, fat owl on decline of the Burrowing Owl in upgraded the Stragglers, prob- stilts. With its long, almost bare legs, many parts of its range. Modi- Burrowing ably non-breed- stubby tail and plump body, it is fication of native plant commu- ers, have been indeed distinctive. It is similar in size nities, and control programs Owl’s national seen intermit- to the American Robin, with a total aimed at Badgers and ground status from tently over a length from head to tail of about 24 squirrels have reduced the popu- slightly wider centimetres. In the wild, adults weigh lations of these burrowing mam- Threatened area in southern between 175 and 260 grams. Long legs mals, leading to a lack of burrows to Endangered British Colum- help this “ground owl” see over the for owls. Without sufficient bur- bia: east to the low “short-grass” prairie vegetation in rows, they are more vulnerable to in . Kootenay River a landscape with few elevated perches, inclement weather and preda- valley, north to and also aid in running down insect tors, such as Coyotes, hawks, other larg- Horsefly in the Interior, and north prey. Female Burrowing Owls are er owls and weasels. to Comox and Campbell River on slightly smaller than males, an un- Use of crop pesticides may reduce the coast. common occurrence for birds of prey. the abundance of important prey, Because of its low numbers and re- This may be an adaptation for squeez- including grasshoppers and mice. In stricted distribution, the Burrowing ing into narrow burrows. the past, agricultural chemicals such Owl has been placed on British Colum- Adults are a rich sandy-brown col- as DDT may have adversely affected bia’s Red List and is also legally desig- our, thickly spotted with white and buff Burrowing Owl reproduction. It is not nated under the Wildlife Act as an markings on the back; the underparts known how significant these factors Endangered species in this province. are whitish, barred with brown. This presently are in British Columbia. Elsewhere in Canada, the Burrowing colouring provides good camouflage in Some owls are also killed by high- Owl breeds across the grassland region dry grassland habitats. The sexes have way traffic. Naive juveniles that feed of the prairie provinces, where there are similar colouring, although males on road-killed animals or on insects an estimated 1000 breeding pairs. The often appear faded during the breed- attracted by warm pavement at night, prairie population has been declining ing season, possibly from spending are particularly susceptible. since at least 1930 due to grassland more time exposed to the sun. Other features include a rounded head with- The focus of activity for this owl abundance of burrows and food, or out ear tufts, yellow eyes, white eye- is the burrow. Its main use is for nesting, an adaptation for mutual defence. brows and a white throat with a dark but burrows also provide refuge from Colony members can alert each other to brown half-collar. Juveniles have buffy many predators and protection from the approach of predators and join in underparts without bars during the extreme heat or cold. Although harassing them. first few weeks after emergence from capable of digging their own bur- In British During the nest- the burrow. rows in suitable soils, Burrowing ing season, adult Owls in British Columbia occupy Columbia, the males forage over What makes them unique? the abandoned burrows of Bad- Burrowing home ranges that ithin the owl family, Burrowing gers, Coyotes, ground squirrels or are two to three Owls are unusual, differing from marmots. One or more “satellite” Owl is legally square kilometres most other species in many burrows can usually be found designated as in size. The Wrespects: they nest in under- near the nest burrow. These are ranges of neigh- ground burrows rather than in cavities used by adult males during the an Endangered bouring males or in the branches of trees; they are nesting period and by juveniles Species. may overlap often active in broad daylight; and they for a few weeks after they emerge considerably, eat insects as well as rodents. These from the nest. but a small area adaptations for life in a grassland envi- Burrowing Owls have often been re- around the nest burrow is aggressively ronment set them apart from other ported to nest in loose colonies. Such defended against intrusions by other owls, which are mostly forest-dwellers. groupings may be a response to local Burrowing Owls and predators. Burrowing Owls are often seen have been recorded in the Okanagan Present range of the standing about in daylight, giving Valley as early as March, but the majority Burrowing Owl in rise to the belief that they are largely arrive in April. Autumn migration is a Canada and the United States active during the day. However, gradual process extending from July to recent radio-tracking studies indicate October. Wintering locations of birds that most hunting activity occurs from the Interior are not completely from dusk to sunrise. Daytime activ- known, but recent records indicate they ity mostly involves loafing within 50 can travel as far south as the San Francis- metres of the nest or a satellite bur- co area in California. row, although juveniles engage in some daytime feeding near the bur- How do they reproduce? row when insects become abundant ecorded nesting sites in British in mid-summer. Columbia include burrows of the An amazing repertoire of about 17 Yellow-bellied Marmot, Badger, vocalisations has been described for R Coyote, Striped Skunk and Belted Burrowing Owls. The “primary song” Kingfisher, as well as a natural crevice in is a two-syllable “who-who.” This call a railway embankment and an old drain is given only by adult males when near pipe. Nest burrows are usually 1 to 3 m the burrow and is associated with pair long, with a downward slope of about 15 formation, breeding and territory degrees, a J- or U-shaped bend, and an defence. Other sounds include the enlarged nest chamber at the end.Adults “rasp,”“chuck,”“chatter,” and “scream.” show high fidelity to their breeding sites Juveniles make a rattlesnake-like buzz and usually return each year to the same when threatened in the burrow. When burrow or one nearby. purpose of the lining material adults spot approaching predators, Pair formation is believed to begin include: serving as an absorbent; they give warning with a short, low-level when the owls arrive at their nest sites. attracting dung beetles eaten by the “chuck” call, usually accompanied by Males try to attract a female with their owls; masking odours produced by vertical head-bobbing. “primary song,” which is given at the the birds, thereby making detection An endearing feature of Burrowing entrance of a promising burrow. by predators more difficult; and pro- Owls is their tol- Once a female is ducing heat by decomposition to aid Present range of the Burrowing erance of non- Owl in British Columbia enticed to the in the incubation of the eggs. threatening site, courtship Egg-laying in the interior of human activity. antics involving British Columbia begins in late April Nests are some- various pos- and early May, but may be earlier on times found in tures, vocalisa- the coast. In the wild, clutch size nor- cow pastures tions and dis- mally consists of six to ten white eggs. near farm build- plays are under- However, clutches as low as three and ings, at airports taken by both as high as eleven have resulted from or on road sexes, usually captive breeding efforts. The female Kamloops rights-of-way. within 15 m of incubates the eggs for 23 to 27 days. This tolerance, the burrow. The male brings food to his mate dur- together with Both sexes ing incubation and stands guard near their habit of prepare the the burrow by day. Hatched young loafing around the nest burrow or burrow for nesting, using feet, beaks stay in the nest chamber for about two perching on fenceposts in daylight, and wings to scrape dirt out of it. weeks. By this time the young are large make this one of the most observable They often begin these renovations at and the burrow is very crowded, so of all owl species. several burrows, eventually selecting they often stand at the burrow Most Burrowing Owls that reside the best one as a nest site. This is then entrance eagerly waiting for the par- in British Columbia during summer, lined with horse or cow dung or ents to bring food. The young owls migrate south for the winter. They other material. Suggestions about the begin flying at four weeks and can fly quite well when six weeks old. What can we do? They start to hunt for themselves n 1983, BC Environment, with seven or eight weeks after hatch- the financial support of the ing, but can catch insects on the Habitat Conservation Fund, ground even before they can fly. Ibegan an ambitious program During this period the female to increase Burrowing Owl remains near the burrow and helps abundance in British Columbia. to distribute food brought in by Thanks to outstanding co-opera- her mate. Once the young owls are tion from Washington State wild- active above ground, the family life officials, 82 adults and 348 often uses several burrows in the three-week-old juveniles were immediate area. transplanted as family units from Washington to recovery areas near What do they eat? Vaseux and Osoyoos lakes from urrowing Owls consume 1983 to 1990. Broods were placed about 15 percent of their in artificial burrows made from body weight daily. Undigested plastic pipe, with an inverted . Ernest Leupin photo B food remains – mostly hair, bucket at the end for a nest cham- bones and insect parts – are regur- Where do they live? ber. Adult owls showed a strong attach- gitated in the form of pellets, which he major habitat needs of Bur- ment to their broods and continued to are cylindrical in shape, 3 to 4 cm rowing Owls are prairie-like ter- care for them despite the disruption of long and about 1.5 cm thick. Pro- rain with low herbaceous vegeta- the move. The program also included duced at a rate of two or three per T tion, deep soil for burrows, the construction of satellite burrows to day, these pellets accumulate around presence of mammals that excavate provide cover for adult males and to the burrow and provide an indication burrows, and a food supply. give the developing young space to of what has been eaten. Burrowing Owls are adapted to spread out. The staple foods of Burrowing Owls open, usually dry country with short The South Okanagan recovery throughout their range are small vegetation. Being ground-dwellers, it program was initially encouraging. rodents and insects, although they will is difficult for them to detect Between 1986 and 1992, 87 introduced eat other prey if available. Remains of a approaching predators or find prey in owls returned as adults and produced variety of small birds, reptiles, amphib- brushland or forest. They are well a total of about 90 fledged young. Simi- ians, fish and crustaceans have been adapted to grazed rangelands, but lar but smaller introduction programs recorded at nest sites. In British find croplands less suitable. Their have also been carried out at Cache Columbia, recorded prey items include preferred terrain is often flat, but Creek and Douglas Lake, using juvenile the Great Basin Pocket Mouse, Deer rugged landscapes are also used. The owls hatched in captivity at Mouse, Western Harvest Mouse, voles, extent of suitable habitat is quite the Owl Rehabilitation Centre in frogs, toads, birds, crickets, beetles, restricted in British Columbia. Ontario. The long-term success of scorpions and grasshoppers. Over much of its North American these programs will be judged by Burrowing Owls are versatile in range, this owl is most abundant in whether self-sustaining wild popula- their methods of capturing prey. They active colonies of ground squirrels or tions become established. chase down grasshoppers and beetles prairie dogs, where numerous nesting The emphasis of the Burrowing on the ground, use their talons to catch and satellite burrows are available. Owl recovery program is now on large insects on the wing and hover in This indicates that the availability of captive breeding in wildlife rehabili- mid-air before swooping down on burrows is a major factor controlling tation centres at the Kamloops unsuspecting prey. They also watch the abundance of Burrowing Owls. Wildlife Park and in White Rock patiently from perches, then glide Burrows dug by Badgers are also (the latter having been moved silently toward their target. Like other important in many areas. In British from Stanley Park in 1997 but still owls, this species probably relies on Columbia, habitats that are otherwise maintained by the Stanley Park acute hearing as much as eyesight for suitable for this owl have relatively Ecology Society). Owls raised in capturing prey at night. few burrowing mammals. these facilities will mostly be released . . . . Ernest Leupin photo Ernest Leupin photo Ernest Leupin photo as yearlings, thus avoiding the high mor- co-operation of the land owners and tle ground-owls may become firmly tality faced by hatchlings in the wild. establishing stewardship agreements. and permanently established in our From 1992 to 1997, 108 captive-bred With public support, these curious lit- southern grasslands. owls were released into the wild. These, in turn, successfully raised 30 young. Criteria for choosing release sites included historic and current owl sight- ings, overall grassland condition, avail- ability of rodent habitat, grazing regimes, land ownership, feasibility and the long-term availability of habitat. Some of the sites were on private land. In addition to releasing the owls, biolo- gists have been conducting research on habitat quality, prey availability, fledging success and return rates. , : The long-term goal of the BC Min- Wildlife Branch istry of Environment, Lands and Parks Ministry of Environment, Lands and Parks is to establish self-sustaining popula- PO Box 9374, Stn Prov Govt tions of at least ten breeding pairs of Victoria, British Columbia V8W 9M4 Burrowing Owls in each of five differ- ent locations in the Southern Interior. This program is part of the National Recovery Plan developed in collabora- tion with Alberta, Saskatch-ewan, Manitoba, the Canadian Wild-life Ser- vice and the World Wildlife Fund. The outlook for Burrowing Owls in British Columbia is still unknown. Although habitat loss is an on-going --- . problem, many human-caused impacts . , are less severe now than in previous years. As most of the grasslands used by these owls are on private lands, the key to the recovery is ensuring the Printed in British Columbia on recycled paper with vegetable inks ..