Sunday, November 28, 2010
M.A.R.S. Moment 2010 – Pygmy owl study
Many people that I meet still think that Mountainaire Avian Rescue Society is “just for the birds”, but there is so much more. Our main focus is to rescue rehabilitate and release wildlife; we do not accept domesticated or invasive species, such as rabbits, pigeons, chickens and starlings. Over the years M.A.R.S. has also been involved in a variety of scientific studies related to local species including, banding hummingbirds, West Nile Virus, poisoned eagles and Trumpeter swans.
Often these studies have involved collecting specimens after their demise so it was really exciting to be asked to take part in a live study. In February the Ministry of Environment together with Pacific Northwest Raptors in Duncan, and M.A.R.S. launched a new pilot project on the release of juvenile pygmy owls into the wild after time spent in rehabilitation, and the feasibility of radio tracking the owls on Vancouver Island. The pygmy owl is Canada’s smallest owl standing a mere fifteen centimetres tall. There are four sub-species of pygmy owls and the local one is the “Swarthi” species.
These little owls are ferocious daytime hunters which makes them a perfect species to track. Perfectly camouflaged to fit in with their habitat that includes mixed forestland with nearby open fields or farmlands, they also have a unique feather pattern on the back of the head that resembles a pair of eyes, much like some butterflies and fish. Although there have been previous studies conducted on adult pygmy owls none have been on juvenile birds. There is very sparse knowledge of their general biology including, nesting success, longevity, survival and range. Why is this study important? It is hoped the information collected will provide a greater understanding of the pygmy owls’ habitat requirements, as well as feeding and reproduction habits. In order to make this study work it was necessary to use telemetry to track the health, activity and movement of the owls.
Obviously with such a tiny owl a special device was needed to transport the transmitter that would not impede flight or cause an injury to the bird. Four owls were used for this study, all were juveniles, two male and two females, that had been separated from their parents. The two owls in the Courtenay area had been in the wild hunting on their own, the Duncan pair were rescued as owlets and had not been exposed to the wild. Three different options were explored to carry attach the transmitters to the body the one that was chosen was a specially designed “back pack” which fitted around the body under the wings holding the transmitter in place along the owls back. The apparatus could only weigh 3% of the total body weight and this was thought to be the least invasive and most efficient design.
Trials were conducted at M.A.R.S. and in Duncan to help the owls get used to flight with the “back-packs” during which time they were closely monitored; unfortunately one of our little owls it did not make it to the field study after escaping through a tiny hole in pursuit of a mouse ending up with three recovering eagles.
Initially the study was to take place in late spring but more time was needed to fine tune the designs and acquire the necessary tracking equipment. Mid September finally saw the start of the tracking, the Duncan owls were released at an elevation of approximately four hundred meters, but they promptly headed for lower ground, unfortunately both were predated upon within the first week, they were collected and will provide feathers for blood and DNA samples. The Courtenay Owl was released in the Trent River area of Royston and was successfully tracked for 3 weeks.
During the field study many volunteers, myself included, went “bushwhacking” through the forest and farmers fields tracking the radio signal and locating the owl. A detailed log was kept mapping the locations, recording the weather conditions and the appearance of the owl, he even had a mouse in his talons one day! Our study ended a little prematurely after the owl had become snagged by the apparatus on a piece of barbed wire, fortunately we were making daily visits and he was none the worse for wear and was released back to the wild. The data showed that this owl had stayed within a five hundred meter radius.
All of the data complied will be used to understand more about these secretive creatures’, it will also become part of the classroom educational programs offered by M.A.R.S. The study was recorded on video, and this was shown at the Harvest Banquet, held on October 30th. This study could not have been conducted without the help of many volunteers, and generous funding from T.D. Friends of the Environment, Holohil, and Timberwest. A big thanks to the land owners and farmers who allowed us access to their property. For classroom bookings please email, email@example.com , to report injured wildlife please call 1-800-304-9968.