POUI.tr Y NOTSS. 4^ 



Seasonal Distribution Oi? Egg Production. 

 It is, of course, a well known fact that egg production is not 

 distributed equally over all seasons of the year. In general 

 there is a tolerably close accord between egg production and the 

 four seasons of the year— spring, summer, fall and winter. The 

 usual relation in the northern part of the country is that pullets 

 hatched in the spring begin to lay sometime in the late fall, and 

 lay more or less well during the winter according to a variety of 

 circumstances. In the early spring they begin to lay heavily and 

 keep this up usually throughout the spring. In the summer the 

 egg production drops off and, finally, in the fall, molting occurs 

 and the production drops very low during the early fall months. 

 The details regarding the ' seasonal distribution are well 

 brought out if the average production for each month of the 

 year be plotted as a polygon. Such a diagram has been pre- 

 pared for this bulletin and is shown in Fig. 9. This polygon is 

 based on the Station's egg records collected during the past nine 

 years. The average production for each month as plotted m 

 the diagram is the weighted mean production for that month 

 based on all the normal records which exist at the Station. In 

 calculating these general means the average egg production for 

 a particular year is weighted according to ^the number of birds 

 which were trap nested that year, or, in other words, according 

 to the number of birds which made the average. 



