a life table for this species. The result differed slightly from one 
constructed by Deevey (197) from Nice's published data (1937). Many of 
Mrs. Nice's observations were concentrated on the first and second 
broods of this species; a precise picture of reproductive success in 
later broods is still needed. 
Abridged life tables cover only a part of the life span of a 
species. The term usefully distinguishes those that involve only the 
subadult and adult stages of a bird's life. Such life tables, in vary- 
ing form and with varying amounts of data, are found in the reports of 
banders who retrap birds over a period of years; they also are repre- 
sented in the composite life tables that have been described aroxe 
and that form the main basis of the present study. 
Summary 
| Although life tables have long been used to summarize vital 
statistics, data for wild populations have become available only within 
the last twenty years. An important component of them is the survival 
curve, which tends to be either concave and J-shaped (teleost fishes, 
song sparrows) or convex (Dall sheep, rotifers); an intermediate type 
(straight-lined on semilogarithmic paper) involves constant mortality 
rates for successive age intervals and typifies the adult stages for 
many birds. The columns of a life table give it a definite and use- 
ful structure. In this paper, such a table is said to be a dynamic 
one when all the animals are born in the same period; it is time 
specific when both survival and mortality data are gathered in a 
single period--and the animals are born in different periods. Cen- 
tralized banding files yield an intermediate type, called a composite 
life table in this report. Life tables may be further identified as 
complete or abridged. The former is still very rare in ornithology; 
the latter type, covering only the subadult and adult stages of a 
bird's life, comprises the main subject of the present investigation. 
