19039
They are often included in the genus " Apus " but they are larger than other members of that genus , their nestlings have a different foot structure and they host different species of feather lice .
 Apus
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 Apus