Fecal sac removal by tree swallows: the cost of cleanliness.

Agriculture & Biology

• nest boxes 75%
• water birds 73%
• birds 72%
• nestlings 61%
• Tachycineta bicolor 44%
• water 36%
• clutch size 32%
• feces 24%
• predation 23%
• nests 23%
• prediction 20%
• energy 17%

Earth & Environmental Sciences

• bird 100%
• nest box 67%
• cost 62%
• land 33%
• water 30%
• nest 22%
• predation 18%
• energy 9%
• rate 6%