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Organophosphate insecticide (famphur) topically applied to cattle kills magpies and hawks

Journal of Wildlife Management

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Abstract

A systematic field study of a black-billed magpie (P. pica) population revealed that magpies and red-tailed hawks (B. jamaicensis) were killed by famphur (= famophos, Warbex) used as a pour-on to control cattle warbles (Hypoderma sp.). Magpie mortality began on treatment day and continued for more than 3 mo. (38 found death); mortality peaked between Day 5 an Day 13. Estimates of magpie density (based on transects) decreased in both the control and treatment areas, but the decrease was greater in the treatment area. A red-tailed hawk found dead on Day 10 had eaten a famphur-contaminated magpie. Another red-tailed hawk was found alive but immobilized, and a 3rd died outside the study area. Brain cholinesterse (ChE) activity was 70-92% depressed in all dead birds examined; famphur residues were detected in all 17 magpies and the 2 hawks analyzed. The amount of famphur obtained by the dead magpies was estimated at 5.2-6.1 mg/kg (based on residue concentrations in the gizzard), which was above the acute oral LD50 for several bird species. The cow hair portion (12%) of the pooled gizzard contents from 13 other dead magpies produced extremely high famphur residues (4600 ppm). The residues persisted on cattle hair for more than 90 days post-treatment. Magpie populations in the far western states declined between 1968 and 1979, which corresponds with widespread use of famphur, although other factors may be involved.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Organophosphate insecticide (famphur) topically applied to cattle kills magpies and hawks
Series title:
Journal of Wildlife Management
Volume
49
Issue:
3
Year Published:
1985
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
648-658
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Wildlife Management
First page:
648
Last page:
658
Number of Pages:
11