by RONDA PAYNE
DELTA – Most commonly recognized by its white, mask-like face, you’ve likely seen a common barn owl and not given it much thought. Generally preferring a diet of tasty rodents, the barn owl is a friend to agriculture (a nesting pair and their chicks can eat more than 1,000 rodents per year), but a friend that is sadly being eliminated from more urban agricultural areas.
“They get hit by trucks when they fly over freeways to the grasslands to hunt,” says barn owl researcher Sofi Hindmarch. “But, I am happy to say that barns owls are still a common sight in the agricultural lands of Delta and Surrey and sometimes even in more urban areas.”
Hindmarch has been researching barn owls in the Lower Mainland since 2007 when she began the study for her thesis in biology at SFU. A wildlife enthusiast, she has found that in the Surrey/Delta region the two factors that have most negatively impacted barn owls are highways and the reduced availability of roost or nest sites. Though her thesis is completed and she has a related job with Canadian Wildlife Service, she continues her work with the owls in this region. “I’m hoping we can install some more nest boxes in high risk areas,” she says.
Leg banding
On a hot July evening, Hindmarch prepares to band the legs of two 40-day old chicks on Westham Island, west of Ladner. At dusk, she pulls out her equipment and approaches the large owl house that has been constructed in the National Wildlife area. She says it’s easy to continue the work because she has the permits and knows the people to contact; but more likely, it’s her love of the birds that keeps her doing it.
“It takes more than two years to determine trends,” Hindmarch notes. “The impact of development, different crops and other factors takes time to see. Five to 10 years would be more significant.”
Taking the information a previous student collected in their thesis research in the early 90s, Hindmarch had a good start to her data and contacts. She stopped at all likely buildings and barns and talked to people. She found that 95 percent or more of those she spoke to were eager to help her and knew if they had a barn owl.
Hindmarch is thankful for the farmers who value the birds.
“I think they (farmers) find comfort that they are very routine birds. They will sit on the same beams and do the same things except when having chicks. I’ve seen people get attached to them, like pets, and they get a bit worried when we are banding them.”
No wonder those in agriculture have come to value the barn owl and its nightly hunting routines. The rodents they eat can often be destructive – field mice, moles, voles, rats and even some small birds like starlings, sandpipers, flickers and hermit thrush. While they don’t often eat pigeons, they do help to keep the pigeon population low and with a life span of up to 20 years (when in captivity, away from danger) they will help farmers with these pests for a long time. In 2007-08, Hindmarch checked 143 potential nest/roost sites and monitored 54 nest sites on a weekly basis. During that time, 134 fledglings were banded to enable the collection of information on their growth and diet. The bands are small metal rings that attach safely with pliers. The owls are frightened during the process, but are calmed when a cover is placed over them. They are treated gently and with respect.
Barn owls tend to mate for the long term and take on specific roles during the demanding nesting process. The female will lay eggs, smaller than a ping pong ball, on average every other day. When all the eggs hatch, there can be a significant weight difference. In most cases, the youngest chicks will die of starvation but will be consumed to ensure there is no waste.
In the month before the eggs hatch, the female stays on the nest, heading out for only 15 minutes a day. This leaves the feeding responsibilities to the male who brings food to her before the chicks hatch and to the female and the chicks for two to three weeks after the hatching.
“He is very busy!” jokes Hindmarch of the male’s duties. Flight is challenging for the young owls and they receive a significant amount of coaching from their parents. The chicks will be about two months of age before they even begin their flying training.
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As Hindmarch begins the process of banding the two chicks she has found, they kick with their back legs, revealing the strength of their fully-developed talons. “They look a bit like dinosaurs in their early days,” she notes. “They have strong dangerous claws they develop early as a defense. The wings grow rapidly as they get older.”
The barn owl is not a well-insulated bird, so they are primarily found in the southern parts of the province and on Vancouver Island. Unlike nesting song birds, they aren’t fussy and will nest in unlikely places, creating quite a dirty, messy environment for themselves. It may be messy, but they are quite territorial about their established home.
The downy chicks Hindmarch has found are beginning to lose their soft white down and are developing their primary feathers in beautiful shades of brown. They are gently returned to their nest house and are heard hissing, not hooting. Barn owls, unlike other varieties of owls, don’t hoot, they screech, scream, twitter or hiss depending on their message. Hissing is definitely a defensive warning. Sometimes called ghost owls, demon owls or hobgoblin owls, in the past these creatures were though to be devious, instead of the helpers they are. Farmers who want to encourage the barn owl population can help by putting up a nest box, ensuring there is some pasture or hayfield where rodents can be hunted and making barns and buildings accessible to the owls by leaving openings they can access.
For more information on barn owls in the Lower Mainland, contact Sofi Hindmarch at [sofi.hindmarch@gmail.com] or 778/238-7380 or visit her research website at http://www.sfu.ca/biology/wildberg/sofi/index.htm.