74 A. E. Hamerton—Diseases of Aviary Birds


in which nearly every bird has died from mycosis shortly after arrival.

Aspergillus fumigatus is the commonest fungus causing mycotic lesions

in birds. The primary deposit usually occurs on the inner surface of the

large thoracic and abdominal air sacs, in which they spread and

coalesce, to form a tough, yellowish, leathery, mouldy film, lining the

whole of the inner surface of large air sacs ; or the growth may com¬

pletely fill the air sacs of small birds with hard yellow nodules, which

may occur in the air spaces of the lungs, where they cause inflammatory

consolidation, distinguishable from tuberculosis only by microscopical

examination. In some cases the mycotic growth is found only in the

syrinx, where it causes death by choking of the windpipe. The disease

kills slowly, and can often be diagnosed during life by the gasping and

laboured respiration of the birds. When recognized, a sick bird should

be segregated.


(4) Deaths Caused by Animal Parasites .—External parasites are

responsible for ill-health among aviary and domesticated birds that

are kept under insanitary conditions, but they are rarely a primary

cause of death. More than forty species of lice occur among aviary birds.

The common bird flea (Pulex avium) infests many species of birds, and

the red mite is a nocturnal blood sucker that causes loss of blood and

intense irritation. Scaly leg or foot mange is caused by a species of

sarcoptic mite, and another species infests the portions of the quills

that lie beneath the skin, and causes loss of feathers. The fowl tick

infects poultry and Canaries, and carries the fatal spirillum fever of

birds ; fortunately a rare disease in England. Internal parasites may

be dangerous to birds, and often cause death.


The following are common and destructive among aviary birds :—


Gape Worms (Syngamus trachealus) infest the air passages of certain

cage birds, Waterfowl, and Pheasants, and cause death by blocking

of the air passages, or by causing inflammatory conditions of the

lungs.


Round Worms (. Nematodes) are common intestinal parasites, and

sometimes cause death by perforating the gut. The most destructive,

however, are the following :—


Heterakis .—Small round worms from 31-2 cm. in length, easily

seen by the naked eye, infest the caeca of birds, and cause severe



