poisoning of raptors with organophosphorus and carbamate ...

8 M•NE^V ET AL. VOL. 33, No. 1
Table 4. Summary of pesticides implicated in Canadian raptor kills (1985-95) according to whether they are thought
to have been the results of labeled use, abuse, spill or where the use pattern was unknown.
No.
INCIDENTS
Pesticide
LABELED UNKNOWN MINIMUM
USE ABUSE SPILL USE TOTAL NO. BIRDS
azinphos methyl -- -- -- 3 3 3
carbofuran 3 6 -- -- 9 28
fensulfothion 1 -- -- -- 1 3
fenthion -- 1 -- 1 2 3
fonophos 8 -- -- -- 8 9
parathion -- -- -- 4 4 4
phorate 3 2 -- -- 5 34
terbufos 3 -- -- -- 3 3
unknown OP -- -- -- 4 4 4
unknown CB -- 1 -- 1 2 3
unknown OP or CB -- 1 -- 16 17 18
Mixtures
carbofuran and terbufos -- 1 -- -- 1 4
phorate and ethion 1 -- -- -- 1 1
phorate and methamidophos 2 -- -- -- 2 4
terbufos and pirimicarb 1 -- -- -- 1 1
Totals 22 12 -- 29 63 122
treatment of warble fly in cattle until June 1994
and may have been used historically to treat sheep.
Therefore, any presence of lamb's wool and fenthion
in a British raptor automatically precipitated
a diagnosis of abuse whether fenthion was used
with the willful intention of killing raptors or
whether it represented an unregistered attempt to
kill ectoparasites in sheep. Nevertheless, the frequent
presence of bait material as well as the frequent
use of products clearly not labeled for crops
grown in the area where most of the incidents occurred
(e.g., the case for most mevinphos incidents)
did indicate that most raptor incidents in
the U.K. were the result of deliberate abuse. Spierenburg
et al. (1990) reached a similar conclusion
in the Netherlands following a review of 143
poisoning incidents occurring between 1975-88.
In France, Berny (pers. comm.) also identified
abuse as a major cause of incidents following a review
of approximately 150 poisoning incidents investigated
between 1991-96. Although most cases
of deliberate abuse resulted from attempts to kill
wildlife regarded as pests, the use of pesticides
in poaching wildlife for human consumption may
also be endemic in some areas. In some
cases, game birds are targeted and raptors are sec-
ondarily poisoned and, in others, raptors are targeted
directly. For example, both situations have
been recorded in South Africa where vultures were
sought after as a source of traditional medicine
(van Jaarsveld 1987, Fourie et al. 1996, Verdoorn
in press). The poisoning of ponds and waterholes
with pesticides is used to harvest game species in
Southeast Asia (Thiollay pers. comm.).
In contrast, pesticide abuse is thought to be less
prevalent in North America. In his review of U.S.
poisoning incidents, Grue et al. (1983) document-
ed five cases of abuse relative to 26 cases of unin-
tentional poisoning with OP pesticides. No raptors
were found in any of these incidents. We estimated
that, between 1985-94, there were 73 reported
abuse cases relative to 64 labeled-use incidents for
raptors specifically (Table 2). In Canada, labeled
cases outnumbered abuse cases by a 2:1 ratio. In
fact, circumstances surrounding most of the cases
in the unknown category were highly suggestive of
labeled use. Where ChE inhibitors were con-
cerned, raptors in North America were at least as
likely to be killed from a labeled pesticide use than
from a willful attempt to poison them or some other
vertebrate. One of our goals was to explore the
apparent discrepancy between North America and