os 
1s 
which interferes with this is found to have an influence upon the regularity 
of the growth of the feather. Thus any of a great number of influences 
may be at work, either together or separately, tending to interfere with 
the well-being of the bird; and it follows that all the causes which have 
been assigned by the practical farmer as concerned in the production of 
bars probably have their justification to a greater or less extent. We 
need only mention: («) insufficiency of suitable food, especially during 
droughts; (6) ailments and accidents of every kind; (c) exposure to 
inclement weather or to rapid changes of temperature; (d) the presence 
of internal and external parasites and the treatment against them; (c) 
weakening of the constitution by in-breeding; (f) lack of variety of food 
and place; and (g) rough handling during the operations of clipping and 
quillmg. Anything in fact which interferes with the proper nutrition 
of the bird has been proved over and over again to influence the produc- 
tion of the faults. Beyond all these a great deal seems to depend upon 
the individual constitution of the bird, and even upon the individual 
feather. Often among birds in the same troop and apparently in equally 
good condition of health the feathers of some will be barring while others 
are perfect, and nearly always in a complete crop some plumes will be 
barred and others free. 
Again seasonal changes have often a marked influence on the barring 
defects. The ostrich is undoubtedly in a more vigorous feather-producing 
condition at certain times of the year than at others. In the Eastern 
Province feathers grown during the dry winter months—May to August— 
are rarely as good and free from bars as those grown in the spring and 
summer months when green food is abundant. 
The defects are just as frequent, if not more so, in superior feathers 
as in inferior plumes. One often sees high grade feathers deeply barred 
towards the tip while short, stalky plumes are uniformly grown. Indeed 
the short stiff feathers occasionally growing alongside high grade feathers 
are less likely to be barred than the latter. It may be held that the 
greater the blood supply in the medulla the more likely is the blood-pressure - 
to undergo such changes as would result in the production of a bar. 
Is tHE Ostrich Morr SuscEePTisBLe To BARRING THAN OTHER BIRDS. 
It may be asked whether the ostrich is more susceptible to feather 
defects than other birds. It is now well established that bars may be 
found in a state of nature in the feathers of all kinds of birds, and can 
be produced artificially by subjecting them to adverse conditions, such 
as starvation, henee the term “ poverty bar’ It must be acknowledged, 
however, that in no bird do they appear to be formed so readily and so 
consistently as m the ostrich, for they are prevalent in the wild as well as 
in the domesticated state, and no plumage is ever wholly free from them. 
In certain other birds, however, I have found that at times the defects. 
are just as plentiful as in the ostrich. Several Black Minorca fowls in 
my possession have the wing and tail quill-feathers quite as strongly and’ 
regularly barred, in proportion to the size of the feather, as in any ostrich 
plume. There is reason to suppose that in these particular fowls in- 
breeding has taken place to a considerable degree, and this may have re- 
duced the constitutional vigour. Also in a South American ostrich, 
Rhea americana, in ihe Albany Museum, the entire plumage, including 
all the body feathers, is barred in a greater proportion than I have ever- 
observed in the African ostrich. 
From a general survey of the situation I am convinced that the pro- 
duction of a perfect plumage is a much more delicate matter in the os- 
trich than in birds generally. All the wild and domestic birds with: 
