Eggs of the 
Sparrow Hawk. 
(93) THE BIRD WORLD. 
nests, I had an opportunity of visiting 
four only, after the young were pretty 
well grown; one of these contained three 
females, two others two females each, 
while the fourth (the nest which escaped 
in 1905) produced three females and 
one male. This latter nest, in 1905, 
contained four females and one male. 
Concluding Observations. 
Now in summarising these observa¬ 
tions we have first of all one or two 
facts. In 1905 four young females un¬ 
doubtedly produced heavily-blotched 
eggs ; in 1906 in at least three instances 
young birds laid pale eggs. The nest 
containing pale eggs in 1905 had eggs 
similarly coloured in the following year. 
How far the good or bad season may 
have influenced the colour of the eggs 
can only be conjectured. In the 
majority of cases in either year it is 
beyond doubt that the pair consisted of 
an adult male and a youne female; 
while if it be conceded that the same 
males returned to their old nesting sites 
in 1906, then we find that in that year 
the result of a new mate was the pro¬ 
duction of eggs of a different type in 
every instance. In the solitary case' in 
which the same female presumably re¬ 
turned the same type of egg was 
continued. The further inference 
might be drawn that some of the females 
who laid pale eggs in 1906 were the off¬ 
spring of the light-coloured eggs which 
hatched out in the previous year; but 
there, perhaps, the matter becomes too 
problematical to be worth pursuing. 
Interesting Comparisons. 
As possibly bearing upon the same 
point, I have these further observations 
to make. Last year there was a Tree 
Pipit’s nest on a railway bank contain¬ 
ing the streaked variety of eggs. This 
year there was a nest near the same spot 
in which similar eggs were produced. 
Shortly after she began to sit the hen 
was killed, and the nest deserted. Soon 
afterwards another nest was made within 
a few feet of the old site, and in it a 
brood was reared from eggs of the 
ordinary red variety. Whether or not 
the same male was the father of the eggs 
in each case it is not possible to say 
with certainty, but there is a strong pro¬ 
bability that he was, and if so then the 
type of egg depended upon the female. 
In another case a Red-backed Shrike’s 
nest containing the red type, of egg was 
taken, and the male killed. A month 
later another nest had been built in the 
same bush and contained similar eggs. 
Of course, it is not pretended that either 
of these cases is either remarkable or 
convincing. Evidence of a negative 
character seldom is so, and it is only 
by the accumulation of a large amount 
of similar data that we can hope to get 
nearer the truth, and establish any rules. 
A Pertinent Question. 
Why is it that only some birds rear 
two or even three families each summer ? 
And why just those that do ? And are 
they the same couples? Of course, it 
is easy to say that they are, but, as both 
males and females of a species have a 
way of strongly resembling one another, 
scientific proof of such a statement is 
less easy than at first sight it appears. 
One very strong reason, however, for 
regarding these prolific parents as 
matched for, at any rate, the season, is 
that we do not see the cock birds show¬ 
ing off their fine feathers to admiring 
hens in June as we did in April. As 
each new mate would, we must imagine, 
have to be wooed ere she could be won, 
the absence of this acrobatic courtship, 
in which even the dusty Sparrow 
spreads his ragged tail as if he were a 
Peacock, lends favour to the view of 
one wedding only in each year. 
