“The video clip above captures the moment when two of the Welcome Swallow (Hirundo neoxena) chicks LINK produced faecal sacs seconds after being fed.
“Immediately upon receiving food, each chick turns around and protrudes its rear upwards. A white membranous sac extrudes from the cloaca of the chick and the parent bird picks it up and flies off with it (above).
“This inbuilt behaviour, common in passerines, assists with nest hygiene and possibly reduces predation of the chicks.”
Note the prominent light yellow oral flanges in the three chicks LINK.
Teo Lee Wei & K.
19th December 2013