"Anna Noyd-Dryver" wrote in message
...
It's like with poisonous caterpillars: the one eaten caterpillar is dead
anyway but the bird remembers and does not pick that species a second
time.

We have some very thick blackbirds that just do not learn. My wife planted
some crocuses. When they came up a year-and-a-bit ago, a blackbird had gone
along and dug up each crocus shoot, thinking it was a juicy worm. It didn't
try the first one, find it wasn't what it thought it was and abandon all the
rest of the things that looked the same. No, it took out every single one of
them - and left the evidence alongside. Grrr. This year it seems to be been
a lot more sensible - or maybe the dunce blackbird didn't survive the
winter.