- Nestlings begin producing
fecal
sacs within hours of hatching
- Fecal sacs increase in size with
age
- Averaging about 2-3% of their body
weight throughout the nesting
period
What is
the Value of Fecal Sac Disposal ?
- Excreting fecal sacs provides a clean nest
preventing contamination of young, their food
and the brooding parent
- Makes the nest less conspicuous
American Robin