3.3. Horned lark experiment
We observed no mortality and no overt signs of
zinc phosphide toxicosis during our horned lark experiment.
Larks consumed more untreated oat baits (0%
anthraquinone and 0% zinc phosphide) than those treated
with 1% or 2% anthraquinone and 2% zinc phosphide
(F2,165 = 149.73, P < 0.001). We also observed a group-byday
interaction (F12,165 = 12.16, P < 0.001); larks consumed
more untreated baits on test days 2–5 relative to test
day 1 (Tukey P < 0.05). Larks consumed an average of
0.4 g of untreated oats, and 0 g of oats treated with
1% or 2% anthraquinone and 2% zinc phosphide (Tukey
P < 0.05). Thus, anthraquinone successfully prevented consumption
of 2% zinc phosphide baits by horned larks in
captivity.