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Conservation Translocation to Circumvent High Hatch-Year Mortality and Increase Site Fidelity: Burrowing Owl Head-Starting in Alberta, Canada - Graham Dixon-MacCallum

Wednesday, November 15, 2023
12:10 PM - 12:20 PM
Sirius / Pleiades Room, Esplanade Hotel Fremantle

Speaker

Mr Graham Dixon-MacCallum
Population Ecologist
Wilder Institute | Calgary Zoo

Conservation Translocation to Circumvent High Hatch-Year Mortality and Increase Site Fidelity: Burrowing Owl Head-Starting in Alberta, Canada

Abstract

Burrowing owls (Athene cunicularia) are threatened or at-risk throughout much of their distribution in western North America. Sharpest declines have been observed in the breeding populations of the Northern Great Plains, and in Canada they are listed as Endangered. For Canada’s Burrowing Owl populations, the most limiting life-stage is the ½-year period from juvenile to 1st-year adult. To test if the population bottleneck during this life stage could be circumvented, a head-starting project was initiated in 2016. Burrowing owl nests were located each spring and youngest brood-members were taken into human care when > 20 days old. These owlets were held over winter until being soft-released the following spring as adults near capture sites. Between 2016 and 2022, we brought 94 owlets into human care and we released 93 owls: 42 male-female pairs, and 9 lone females. We tracked 81 owls post-release with satellite transmitters, and released 12 owls without transmitters. To control for possible transmitter effects on survival during migration, we removed 21 transmitters at the end of the breeding season. Released owls initiated 46 nests, of which 37 were successful, fledging 195 owlets. To date, 1 banded-only owl has returned from migration to breed for a 2nd time, and 1 owl migrated and survived winter carrying a transmitter. In addition, through band re-sighting, we confirmed a minimum of 12 (6%) offspring produced by head-started owls migrated and returned to our study area. Head-starting shows promise but further study is needed to develop strategies for improving survival on migration.

Biography

Graham leads a burrowing owl conservation translocation project for the Wilder Institute/Calgary Zoo in Alberta, Canada, and has also studied anti-predator behavior in a conservation breeding population of Vancouver Island marmots. Graham completed a B.Sc. in Biology at Acadia University and an M.Sc. in Biology at the University of Victoria.
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