THE BROODING INSTINCT IN THE DOMESTIC FOWL 279 



BROODINESS NOT PRECEDED BY EGG LAYING OR BY VERY 



LITTLE EGG LAYING 



It was suggested in the preceding section that there was no 

 necessary connection between the number of eggs laid and the 

 manifestation of the brooding instinct. This is very clearly 

 shown by the cases which will be discussed in this section. 

 These are cases in which a bird became broody w T ith little or no 

 antecedent egg production. One of the most striking of such 

 cases in all of our statistics is that shown in Fig. 10, which gives 

 the egg record for bird No. 699 from November 1 to July 1. 



It will be seen that this bird went broody on May 10. The 

 only record of egg production before that time is a single egg on 

 November 27. There is every reason to believe that this record 

 of November 27 is an error, probably to be accounted for as an 



Figure 9. Showing the record of bird No. 699. 



instrumental error of the trap-nest operation. At the time 

 when this record was made the old style trap-nests were in use 

 at this Station. These were in a number of particulars unreliable 

 (cf. for example Pearl [5] ). General knowledge of the laws of 

 egg production gained through a number of years study of such 

 matters at this laboratory would indicate with great probability, 

 indeed, practical certainty, that this record was an error. How- 

 ever, if it be allowed to stand, it is clear that it can have had 

 nothing to so with the manifestation of the brooding instinct 

 over five months later. Following this broodiness, bird No. 699 

 laid an egg on May 29 and another on June 19. These two records 

 are probably correct, since other similar cases are to be found in 

 the Station records. This case proves definitely that imme- 



