-5- 
I deduce from the mixed composition of pairs, and from the spring influx
of 
larger groups, that a spring shuffle occurs at my station. Its magnitude
is ini 
dicated by the fact that matings with unbanded individuals from outside are
more 
common than matings with banded birds. The shuffle must precede the matings,

which would indicate that it occurs in March. 
I have no direct positive evidence of a fall shuffle, The best test would

have been to band unfledged broods, but I always feared to tear open the
nesting 
cavities too soon, and as a consequenceound the brood alreadI go 
arrived to do the banding 
Most species that shuffle in spring of course do the same in fall. 
Mortality vs. Movement; Turnover 
With this background on movements, I now return the reader back to the shrink-

age series             . Eo-e t GiS %h rt! 
UrLt part of the shrinknge is mortality, and what part movement? 
While movement in and out is known to occur, it is likely that the over-

all duration of the series represents mortality. 4That is to say, the oldest

birds surAViving, unless all the oldest survivors moved out, which is unlikely.

Hence the 5-year duration of the survival series              means that
the 
miximum longevity is 51 years. aM-'thet the average year-class of 9 or 10

dalls below one bird by its fourth yter; . yond the third yoair the   s only

f ractiona1~hance of zUt.'.- i                 44 
Thedeductions Ma     deal with duration   of the shrinkage series. Whether

the rates of shrinkage                 -    L.- have any significance can
only 
be guessed at. The initial new bandings for some years include some spring

influx, and for some years they include winter evictions that survite else-
          t 
where, but are no longer trappable. Table 1 suggests that steh evictions
may 
have occurred in 1944-45, when an initial banding of 11 birds was never later

heard fiom.Both spring influx and winter eviction tend to swell the initial

figure R'beyond the actual population of the home range. Ornthe other hand

4