A "Whalemingo" (plural "Whalemingos") are an alien species first seen in "When Worlds Collide". Tristan is one of them, and their planet almost crashed on the earth.
The average whalemingo is the size of a whale of unspecified species (possibly the blue whale), and are covered in pink feathers like the normal flamingo. The rest of their feathers are the same as flamingos.
Flamingos are pink thanks to some fruits they eat, probably is the same with Whalemingos