Thank you for your question. Because we're not directly involved with species other than the swans, you will probably be able to get answers to your question through the Parks department. Here's detailed contact information.
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Email: pbcomment@vancouver.ca

Phone: 3-1-1 (Vancouver),

604-873-7000 (outside Vancouver)

604-873-7193 (TTY)

Write: Vancouver Parks and Recreation

2099 Beach Avenue

Vancouver, BC V6G 1Z4
(office hours are Monday to Friday, 8:30 am to 5 pm)

I do hope this helps to get you an answer to your query.

All the best!