names of ossif'rag-us, caurinus, corax principalis, or perhaps even 
cryftoleucus. The variation between early and late sets is very great in 
some, and small in other sections of the country. However, some dif¬ 
ference does exist, and always in one way. The eggs in the early sets av¬ 
erage .06X.03 larger than those of the late sets. The latter are not known 
to be second sets, but are believed to be those of the more timid and 
wary birds, building after the leaves have yielded a more effectual screen 
for their nests. While I have no conclusive proof of it, 1 believe the 
earlier sets are those of the older, or more hardy, or better developed 
birds. It is remarkable that the latter not only produce the larger egg, 
but also the greater number in a set. In five instances where it is known 
that the birds laid second sets after the first had been taken, the second 
sets averaged ,o2x.or less than the former, and usually contained one or 
two eggs less in a clutch. 
The average measurements of 979 eggs is 1.65x1.15. This average is 
considerably under that of our professional brethren ; yet in all proba¬ 
bility no average measurement of the eggs of this species is founded 
on as numerous and accurate data as is that just given. 
It has often been a question to many whether the number of eggs in a 
clutch has any influence whatever over the size of the egg. It is often 
remarked that the larger the clutch the smaller the egg, and vice versa. 
This is true to a certain extent; there are, of course, exceptions to all 
rules ; for instance : a set of seven eggs collected in Wisconsin gives an 
average of 1.69x1.19, which is slightly larger than the true average for that 
part of the country. A series of sets of seven (if they could be had) 
might show a very different average. 
The following tabulated form will render this more clear. 
Average size of 21 sets of 6 eggs each, 1.66 x 1.16 
“ 80 “ 5 “ 1.65x1.15 
“ 49 “ 4 • “ 1.66 x 1.18 
“ 16 “ 3 and 2 “ 1.61x1.13 
It will be at once seen that the sets of four average largest, and that 
the sets of five average precisely the same as the total average of all the 
eggs measured (this number is without doubt the. most normal clutch of 
americanus). The slight increase in the average of the sets of six can 
readily be explained. In the first place it has been shown that the sets of 
this number of eggs were all collected very early in the season, and that 
the supposition is that they were from the most hardy and vigorous birds ; 
and again such clutches are .more frequent in the North and West, where 
all eggs average larger. The sets of two and three eggs each, which were 
mostly collected late in the season, are probably second or third clutches 
