The Last Bird of Its Kind, Singing for a Mate That Will Never Come, is the Saddest Thing Ever
In 1987 the last Kauaʻi ʻōʻō was male, and his song was recorded for the Cornell Lab of Ornithology. The male was recorded singing a mating call to a female that would never come.
The ōʻō was endemic to the island of Kauaʻi and was common in the subtropical forests of the island until the early twentieth century when its decline began.
For those interested, you can listen to the uninterrupted version of the song below: