A significant number of migrating owls have kept researchers at the Mugaha Marsh Banding Station extremely busy as the birds move through northern B.C. in unusually high numbers. Jeannine Randall, a bird biologist with the Mackenzie Nature Observatory, located around 200 kilometers north of Prince George, described this year as exceptional. Typically, they catch around 100 owls, but this season they have already captured 266 with two weeks remaining, marking a record-breaking year.
The surge in owl numbers has caused a shortage of the specific tracking bands required for monitoring the birds due to the overwhelming demand. According to Randall, the station faced a scarcity of the larger band sizes predominantly used for saw-whet owls, the primary species they target, as these were on back-order from the bird banding office.
While seeking assistance from other organizations, it became evident that the owl population spike was a widespread occurrence, leading to similar supply shortages at numerous stations. Randall attributes the increase in owl numbers to an abundance of small rodents this year, which are the primary prey for these birds.
Despite the positive numbers observed at Mackenzie, it may not reflect the overall situation for owl species in the province in the long term. Rémi Torrenta, a biologist with Birds Canada, highlighted that many owl populations have been declining over the past 25 years, although some species like barred owls have remained stable or even increased. Torrenta suggested that this declining trend likely affects various owl species in British Columbia, including the northern saw-whet owls.
Torrenta explained that the current high owl population is likely part of a well-documented four-year cycle where an abundance of owls leads to a subsequent crash in the rodent population the following year. This phenomenon, known as a mass eruption, forces the owls to migrate further south in search of food when resources become scarce.
To better monitor these trends, Birds Canada organizes the Nocturnal Owl Survey, a citizen science initiative that relies on volunteers nationwide to track owl numbers each spring. This program aids in tracking owl populations and migration patterns across the country.
The banding project at the Mackenzie Nature Observatory plays a crucial role in broader scientific research by providing essential data for monitoring owl populations and migration routes, according to Randall. Recently, the station recaptured an owl that had been banded in Victoria in 2024, offering valuable insights into the species’ movement patterns and behaviors.
Randall emphasized the importance of studying these findings for effective species management and a better understanding of owl ecology.