8 IOWA STUDIES IN NATURAL HISTORY 
SANITATION 
EXCRETA 
TABLE IV 
Dates Cowbird Red Blue 
De- Car- De- Car- De- Car- 
voured ried voured ried voured ried 
fom: fm £m a ee re 
Monday, July 9 4 5 2 
Tuesday, July 10 1D crit Oraeee 5 3 
Wednesday, July, 11) > 4.) 1) 46, 6) Gio 2s Ah ee, 
Thursday, July 12 52 Fe 16 6. oe ey, + 
Friday, July 13 2. OQ yo i Meee I 
Saturday, July 14 at Migesirqatse Il Ps Tienees Seaman) (ygelhd Wig jc nena) E 
Sunday, July 15 1 A epee ie | (eres 7 5 4 
Monday, July 16 Oe eo Ores 9) EGS 2 ene eae 
Tuesday, July 17 Ona Bisel Bed 
26 15 46 64 23: 12 2375288 22) aloe els) om 
Total amount disposed of (f) 158. 
Total amount disposed of (m) 156. 
It was interesting to observe the way in which this pair of 
small birds worked out the sanitary problem. On visit 336 
this note was made. ‘‘Blue was last fed on visit 311, two hours 
and 89 minutes earlier. During this period no excreta have 
been voided.’’ From this and other data we may conclude that 
food is the excitant which sets in motion the muscles of evacu- 
ation. The records show that it was only six times out of the 
whole number that the excreta sac was voided by a nestling 
other than the one just fed. After feeding, the parent would 
wait a few moments at the side of the nest; as the excreta sac 
appeared it would be seized and devoured, or carried away. 
During the nestling period the excreta sac was voided only 
five times while the old birds were absent from the nest; and 
these all occurred in the later days of the period. It may indi- 
eate an intensification of feeding activity, or it may indicate a 
degeneration of the instinct governing the removal of the 
excreta. The following notation was made at visit 991: 
‘‘Hixereta were voided by Red after the female left the nest. In 
a moment she had returned with a small insect in her bill; she 
ate the insect herself and carried away the exereta.’’ With 
