Pair of owls at Calgary Zoo die from West Nile virus

The Wilder Institute/Calgary Zoo says its great grey owls Catelyn and Arya died suddenly due to West Nile virus. (Facebook/Calgary Zoo)

The Wilder Institute/Calgary Zoo says its great grey owls Catelyn and Arya died suddenly last month due to West Nile virus.

A Thursday social media post from the zoo said the birds passed away on Sept. 15.

Catelyn, a senior bird who hatched in the wild, had been with the zoo since 1997, while Arya hatched at the zoo in 2013 and was 12 years old.

• The information you need to know, sent directly to you: Download the CTV News App

“Great grey owls are highly sensitive to this virus,” said the zoo. “Even with their annual vaccinations, it can sometimes overwhelm healthy individuals.”

The zoo said as a precaution, all the birds in its Jihad Shibley Rocky Mountain Aviary were re-vaccinated and tested, all with negative results.

“Catelyn and Arya were cherished ambassadors for their species, and their calm, captivating presence touched the hearts of staff, volunteers and guests alike,” said the zoo.

“They will be fondly remembered and deeply missed by all.”