118 
them. However, as there is sometimes congestion of blood in the lumbar 
region, breaking the back may cause effusion of dark blood, which obscures 
the small organs, and it is generally better to follow the more careful 
method described above. 
The male organs (testes) are two in number, normally white or 
yellowish in colour, but sometimes darker, and lie side by side. They are 
rounded or ellipsoidal in form, and for some time before, during, and after 
the breeding season, they become very large and conspicuous and can not 
be mistaken. In young birds and in winter specimens the testes may be 
extremely small (less than the size of a pinhead in some species), but can 
usually be distinguished unless broken up by shot wounds or decomposi- 
3 1 
Male 
Adrenals 
Testis 
Kidney 
iatic 
9 \f' A 
Female 
Adrenals 
Ovary 
Kidney 
Oviduct 
Figure 43. Determination of sex of birds by dissection. 
tion. In the small, shrunken state they may not be larger than grains of 
sawdust, but the latter will be unattached and can be wiped off. Do not 
confuse the testes or ovary with the adrenal bodies, which are smaller and 
flatter, yellow or orange in colour, and lying farther forward in the anterior 
border of the kidneys (Figure 43). 
The female organs usually consist of a single ovary, lying a little to 
the left side on anterior surface of the kidney (Figure 43). A vestige of 
the right ovary may be present. During the non-breeding season the ovary 
is a pale-coloured mass of small undeveloped ova, irregular in shape and 
somewhat flattened. The granular structure, or minute divisions, are 
usually visible to the naked eye, but often a magnifying glass is necessary 
to identify the organ. The adrenal bodies are situated as in the male. 
During the breeding season there is no difficulty, as some of the ova become 
enlarged to form the yolks of the eggs, the ova being of graduated size 
according to their maturity. At the same time the oviduct, a tube leading 
from the neighbourhood of the ovary down the left side to the cloaca 
(vent, or common outlet for rectum, bladder, and generative organs in both 
sexes of birds), becomes enlarged, contorted, and whitish in colour. 
