Individual study: Effects of chemical repellents on egg consumption by fish crows Corvus ossifragus, Denver Wildlife Research Center, Florida, USA
Avery M.L. & Decker D.G. (1994) Responses of captive fish crows to eggs treated with chemical repellents. The Journal of Wildlife Management, 58, 261-266
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Use aversive conditioning to reduce nest predation by avian predators
A replicated ex situ trial in the USA (Avery & Decker 1994) found that consumption of Japanese quail Corturnix japonica eggs by 30 fish crows Corvus ossifragus (in five treatment groups) was affected by the injection of different chemicals into the eggs. Topically applying methyl anthranilate to the outside of eggs (alone or in conjunction with injecting 18 mg of methiocarb) reduced consumption compared to other treatments (injection of 18 mg of Carbachol or methiocarb or 18 mg methiocarb plus 100 mg methyl anthranilate). Post-treatment tests with untreated eggs found that only crows from the topical methyl anthranilate groups did not consume eggs on the first day following treatment stopping (only two of 12 birds from these two groups resumed consumption in the post-treatment phase, although seven others moved but did not eat eggs). In a separate experiment, 16 crows in two groups were given eggs injected with either 30 mg methiocarb or 40 mg carbachol for five days. These crows consumed more eggs than those exposed to topical methyl anthranilate treated eggs, but fewer than other previous treatments. Five of eight crows exposed to 30 mg methiocarb and three of eight exposed to 40 mg carbochol ate eggs in the post-treatment test period.