the book contains selected articles covering topics from philosophical
reflections on birds to freeway birding and big sits. It will be
placed in the OG library.
Your editor compiled a set of notes on gull identification from the
program presented by Bret Whitney at the January 1981 OG meeting
(see THE SPOONBILL, April 1981). An amendment is necessary at the
bottom of page 3 ("Plumage Sequences"). Large gulls acquire full a-
dult plumage in their 4th winter, i.e. when they are just older than
3 years. Similarly, medium gulls become adult at just over 2 years, ,
and small gulls at just over 1 year. - 3 .,; *
The April issue of this newsletter ended with a question concerning
bird distributions. More specifically, we asked you to try and name
the seven extant species which are endemic to the U.S. Two months
have passed and the correct answers are as follows 1 Red-cockaded
Woodpecker, Carolina Chickadee, Brown-headed Nuthatch, and Bachman's
Sparrow (all southeastern U.S.)s Brown-capped Rosy Finch (central and
northern Rockies)s Yellow-billed Magpie (California)! Lesser Prairie
Chicken (central prairie states).
THE SILENT KILLERS; DISEASES OF BIRDS
Part 51 AVIAN TUBERCULOSIS
by B. C. Robison, D.V.I
Every historical era, it seems, is afflicted at one time or another
with a disease that is both unique to the times and that is looked
upon with an especial sense of dread. In biblical times, it was leprosy! the Middle Ages had the Black Death: the twentieth century
might well be remembered as tfie Age of the Coronary Occlusion; and
in the nineteenth century it was tuberculosis.
Tuberculosis is a chronic debilitating disease found in numerous species of animalsi it is caused by three species of the micro-organism
Mycobacterium, each of which affects a particular hosts man and subhuman primates (M. tuberculosis), cattle (M. bovis), and birds (M.
Intensive eradication efforts have eliminated bovine TB (formerly a
source of human infection, in pre-Pasteurization days, through contaminated milk), but chicken TB (turkeys are resistant) still persists to the economic detriment of the poultry industry. Affected
birds are unthrifty and unfit for use as food, and produce fewer eggsi
they are also a source of infection in sheep and especially swine,
and, in rare cases, humans.
Among wild birds, TB is uncommon under ordinary open field conditions!
among zoo birds, however, it is more common due to the unnatural conditions of confinement. Certain gregarious species, such as starlings,
have shown to be an important factor in the dissemination of avian TB.
In 1963, an Indiana pig farm had an outbreak of TB that was shown to
be caused by the avian agentj the farm had also been heavily populated
with roosting starlings, and 125 of these birds were subsequently collected and examined. Six percent were found to have TB lesions in
the liver, spleen, and intestines. The nature of these lesions, interestingly enough, suggested that this species of bird is relatively
resistant to the mycobacteria. One-half mile away, a poultry farm
was hit with a TB outbreak about a month earlier, and it, too, had
many starlings on the premises. It was demonstrated that the starlings
contracted TB at the poultry farm, and then transferred it to the
swine operation. Such epidemiologic findings hardly enhance the reputation of this nuisance bird. ■■'■liit? .
The clinical symptoms of avian TB are non-specific. Affected birds
are lethargic, underweight, and suffer pectoral muscle atrophy and
loss of color in the comb and wattles. Often a tuberculous bird will
hop around with a jerky, one-sided lameness because of infection in
the bone marrow of the leg. Occasionally a wing" will droop due to
tuberculous infiltration of the humeral-scapulqcoracoid joint (dat
means de shoulder). Paralysis may occur in advanced cases. Diarrhea
results from infection along the intestinal tract, further aggravating