Monocrotophos-Induced Mass Mortality of Swainson's Hawks in Argentina, 1995-96

Swainson's hawks (Buteo swainsoni) were observed in the grasslands (pampas) of Argentina during the austral summer of 1995-96. Widespread agrochemical use to control insects had a profound effect on flocks of hawks foraging on grasshoppers and caterpillars throughout the pampas. We describe 19...

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Bibliographic Details
Published in:Ecotoxicology (London) 1999-06, Vol.8 (3), p.201-201
Main Authors: Goldstein, Michael I, Lacher, T E, Woodbridge, B, Bechard, M J, Canavelli, S B, Zaccagnini, M E, Cobb, G P, Scollon, E J, Tribolet, R, Hopper, M J
Format: Article
Language:English
Subjects:
Agrochemicals
Argentina
Buteo swainsoni
Cholinesterase
Gastrointestinal tract
Grasslands
Insecticides
monocrotophos
Mortality
Organophosphates
Pampas
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Summary:Swainson's hawks (Buteo swainsoni) were observed in the grasslands (pampas) of Argentina during the austral summer of 1995-96. Widespread agrochemical use to control insects had a profound effect on flocks of hawks foraging on grasshoppers and caterpillars throughout the pampas. We describe 19 mortality incidents and an estimated 5,095 dead hawks. Forensic analysis indicated that the organophosphate insecticide monocrotophos was responsible for the deaths at six separate sites, accounting for over 4,000 of the mortalities. Brain cholinesterase was lethally inhibited (95%) and monocrotophos residues (n=31/45, mean=0.20 ppm, range 0.05-1.08 ppm) were found in the contents of the gastrointestinal tract. No other insecticide residues were found. Sample analyses, combined with interviews with farmers, indicated that monocrotophos was responsible for deaths at 17 of 19 mortality incidents.
ISSN:0963-9292
1573-3017
DOI:10.1023/A:1026496331396