Remembrance Day for Lost Species, November 30th, is a chance each year to explore the stories of extinct and critically endangered species, cultures, lifeways, and ecological communities. 

Whilst emphasising that these losses are rooted in violent and discriminatory governing practices, the day provides an opportunity for participants to make or renew commitments to all who remain, and to develop creative and practical solutions. 

Remembrance Day for Lost Species honours diverse experiences and practices associated with enduring and witnessing the loss of cultural and biological diversity.

And read here an article about grieving for extinct species in the Guardian.