8. Information from dead and dying birds
John E. Cooper
8.1 Introduction
From time to time the avian biologist has access to dead or dying birds. If properly
investigated, these birds can provide information that is either of biological
importance (e.g. morphometrics, molt patterns, samples for DNA) or of rele-
vance to studies on health and disease (e.g. presence of pathological lesions, toxic
residues).
Insofar as the latter category is concerned, dead or dying birds can be used:
(a) to ascertain the cause of disease or death in that individual or population—
a “diagnostic” investigation, or (b) to provide data on background health status,
for example, presence/absence or numbers of parasites, underlying pathology,
body condition—so called “health monitoring.”
These two activities may sound similar but they differ in orientation and value.
Diagnosis is essentially a veterinarytask, aimed at trying to detect and determine
a disease, often with a view to treatment or control. Health monitoring, on the
other hand, is a more broadly based concept that is concerned with developing
a database of factors that might be influencing the survival of individuals or the
status of a population while not necessarily causing clinical disease or death. Such
monitoring is usually an interdisciplinarytask, with an input from biologists and
others as well as from veterinarians (Cooper 1989, 2002) and is increasingly rele-
vant to conservation programs for threatened species (Woodford 2001).
The investigation of birds following an unexplained “die-off ” (mortality on
a large scale) is often a combination of a “diagnostic” investigation and a study
aimed at “health monitoring.” The former, diagnostic work, may provide a cause
of death, and often this is not the most important finding from an ecological point
of view. Thus, many wild birds die of starvation which is fairly readily diagnosed
by an experienced veterinary or wildlife pathologist, but the important question