An inexpensive method for identifying predators of passerine nests using tethered artificial eggs
We identified nest predators of two European thrush and three European finch species in the central North Island, New Zealand, using artificial clay eggs in active natural nests. The acceptance of the artificial egg by females was 75%, with low rates of female egg ejection (7%) or desertion (7%). Due to high predation rates we could not confirm the acceptance of six (11%) artificial eggs before predation occurred. Of the 57 nests that received an artificial egg 30 were preyed upon.