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Murie collected fine specimens of young shore birds in Alaska by taking 
the eggs as soon as they became “pipped” and hatching them in a warm 
place, but this method is not always practicable. 
Downy young birds are somewhat difficult to skin as the skin is very 
tender. The down is also hard to clean if soiled, and it is not easy to 
remake the skins. Major Allan Brooks advises that before attempting to 
skin a “downy”, the collector should make a careful examination of the 
pterylosis or arrangement of the feathers in definite areas of growth 
( pterylce , or feather tracts). If the specimen is overstuffed, the markings 
will be distorted and the short down feathers will not overlap the bare areas. 
A downy specimen will usually make up fairly well if not overfilled, 
especially around the head and upper back, and the skin worked forward 
and not pulled back. 
Make the opening cut along one side of abdomen, and not along the 
middle, to avoid wetness which ensues if the umbilicus is opened. If the 
specimens are to be used in a mounted group, it is well to mount the 
skins in the field, wiring the legs and anchoring them in a small piece of 
cork. Pad with bits of cotton. The orbits should be filled with cotton, 
and the colour of the iris carefully noted so that properly coloured glass 
eyes may be put in later. Also note carefully the colour of bill and feet, 
as in some species the colours of these parts in juvenile specimens are 
unknown to ornithology. 
The sex of young ducks in the downy stage may generally be deter- 
mined by the much greater size of larynx in the males. If several speci- 
mens are in the brood comparisons may be made and verified if possible 
by dissection. 
Determining Sex of Birds 
Determination of the sex of a bird from plumage and other external 
characters can not be depended upon. Male and female of any species 
normally have different plumages at certain seasons, but young birds and 
adults in winter plumage are often hard to tell apart. Female birds may 
occasionally develop male secondary sexual characters through pathological 
conditions. All bird specimens should, therefore, have the sex verified by 
dissection. 
After the skinning is completed, and the body removed, cut open the 
left side from the vent to the anterior border of the ribs. Push the intes- 
tines aside and look for the sexual organs, which lie in the small of the 
back close to the backbone just below or ventral to (on the abdominal side) 
the anterior end of the kidneys. The kidneys of birds differ somewhat 
from those of mammals, being large, soft, elongated, dark brown, irregular- 
shaped masses filling the concavity of the sacrum. 
The writer for years followed Hornaday’s method (1892) of opening 
up the body by a slash across the wall of the abdomen, then breaking the 
small of the back, which snaps off very easily when the front of the body 
is grasped with one hand and the tail part with the other. The intes- 
tines will at once fall forward without any further handling, the rectum 
having been severed early in the skinning operations. The intestines being 
out of the way, the testes or ovary should be plainly exposed. The best 
feature of this back-breaking method is that the sexual organs lie just 
back of the break, and the young dissector knows just where to look for 
