EFFECT OF FLAGGING ON PREDATION OF ARTIFICIAL DUCK NESTS

Nest markers are used commonly to identify and mark locations of nests . However, they also may attract predators and increase nest predation . We tested the effect of plastic flagging on predation of artificial duck nests, during two consecutive 14-d period, along two 45-km segmen ts of graveled road near Crandall, Manitoba, Canada. Estimates of dail y mortality rates between flagged and unflagged nests did not differ, but the power of rejecting the null hypothesis was low. Daily mortalit y rates of nests were higher between day 0 and 8 than between day 8 an d 14. A flag-by-interval interaction was significant, indicating that flagged nests had a higher mortality rate than unflagged nests between day 8 and 14. Differential nest-site vulnerability may affect predati on soon after nest construction, whereas flagging may increasingly inf luence predation as nests age. We recommend that nests not be market w ith flagging and that natural objects be used to aid in nest relocatio n.