4872
The split between this tropicbird and the other tropicbirds , the red-tailed and white-tailed tropicbird , is thought to have occurred about six million years ago .
 animal: white-tailed tropicbird
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 animal: white-tailed tropicbird