LIMITED TRAPNESTING 23 



SUMMARY 



This report includes the first-year records of 1684 Rhode Island Red females 

 hatched from 1936 to 1942. This stock has been bred since 1916 for characters 

 associated with high fecundity. All birds were trapnested from their first pullet 

 egg for a full year. Several different types of limited trapnesting and egg weigh- 

 ing have been applied to these data to test their accuracy for predicting the true 

 record: A, the first two days of each month for varj'ing periods; B, the first week 

 of each month for varying periods; C, daily in October at the beginning of the 

 year; D, daily in August at the end of the year; and E, daily from the first egg 

 to January 1. The value of these limited records has been considered for esti- 

 mating annual egg production, egg weight to January 1, hatching-season egg 

 weight, annual egg weight, age at first egg, intensity (winter, spring, summer, 

 and fall clutch size), winter pause duration, and annual and biological persistency. 



Froni these data, the following conclusions have been drawn: 



1. An accurate estimate of the probable annual egg production can be made 

 by trapnesting two days each month or the first week of each month for twelve 

 months, or daily for the month of August. Trapnesting daily from first egg to 

 January 1 furnishes dependable information, but is not so accurate as the pre- 

 ceding for predicting annual production. Trapnesting during October does not 

 furnish a reliable criterion of annual production. 



2. Mean egg weight to January 1 can be predicted with a high degree of ac- 

 curacy from either two-day weighings or one-week weighings in October, Novem- 

 ber, and December or from daily weighings in October. 



3. An estimate of hatching-season (March) egg weight can be made with 

 considerable accuracy from weights taken on the first two days or in the first 

 week of October, November, and December or from weights taken daily from 

 first egg to January 1. Egg weights taken daily in October are not entirely satis- 

 factory for estimating hatching-season egg weight. 



4. Annual egg weight niay be closely estimated by weighing the eggs on the 

 first two days of each month or during the first week of each month, dail\- in 

 August, or daily from the first pullet egg to January 1. Estimates based on egg 

 weights taken daily in October were not reliable. 



5. Age at first egg may be estimated rather satisfactorily by trapnesting 

 daily in October at the beginning of the laying year, if the birds are hatched in 

 March and April. 



6. Trapnesting for the first two days of each month or for the first week of 

 each month from October through February gives a reasonable measure of winter 

 intensity, as does daily trapnesting from the first pullet egg to January 1. Com- 

 plete October or August records do not give a very accurate measure of winter 

 intensity. Trapnest records made on the first week of each month or on the first 

 two days of each month, or daily in August at the end of the year may be used 

 for estimating spring intensity, and are also satisfactory for estimating summer 

 and fall intensity. 



7. Daily trapnesting to January 1 affords a good measure of winter pause 

 duration. 



8. Trapnesting daily in August afifords a rather satisfactory measure of 

 persistency. 



9. Limited trapnest records do furnish much valuable information, but in an 

 advanced breeding program they are much less valuable than complete trap- 

 nest records. 



