This being me, I'll start with an Australian bird.

This is the Paradise Parrot, a member of the same subfamily as the parakeet, Platycercinae. It was last sighted in 1927. I remember reading about it when I was first getting into birds. As with any recently extinct animal, unconfirmed sightings were still cropping up from time to time. This excited my interest, particularly when we happened to be camping in its habitat a few months later. I spent a lot of time walking through the area around our camp, peering into the light forest around it, hoping to catch a glimpse of it. I was rather disappointed when the time came to leave.