1982] Eisner & Meinwald — Defensive Spray Mechanism 363 
The results, lumped for the 9 feeding sessions with the 3 thrushes, 
are shown in Figure 4. It is clear that the birds rated Necrodes 
distinctly undesirable relative to mealworms. While the latter were 
all eaten outright, 74% of Necrodes were either rejected or left 
untouched. The 26% that were eaten were only taken after repeated 
peckings. A special point was made to check the rejected Necrodes 
for injury. None was found to bear any, and all were live when 
examined several days later. Although it proved impossible to 
determine with certainty whether Necrodes always sprayed when 
pecked or grasped by a bird, in some cases there was evidence that 
discharges had occurred. Streaks of spray occasionally made their 
appearance on the glossy floor of the cage during an attack, or birds 
shook their heads violently after seizing a beetle, as we have repeat- 
edly seen captive thrushes do when attempting to take insects that 
spray (e.g. carabid beetles). 
E EH R NT 
FA TE 
Fig. 4. Fate of Necrodes surinamensis and mealworms fed to three Swainson’s 
thrushes; E = eaten; EH = eaten with hesitation; R = rejected; NT = not touched. 
Details in text. 
