Answer: Birds sometimes seem to peck at the plant but sometimes they are actually pecking at aphids or other insects on the plants, so you might want to look very carefully and see if there are any aphids or slugs or other insects attracting the bird. If it is a crow, it might be attracted to the plant label and be trying to take it.
If the bird is really pecking at the plants, you could try stringing nylon fishing line above the plants in a slightly random pattern. (With a container plant you could try a teepee of sticks inserted in the pot and string the line between and around those.) This is supposed to confuse their depth perception and deter them from landing there. You could also try the flash tape sold at garden centers, or string irridescent cd's or shiny aluminum pie pans above the plants to flash and reflect light and startle them. Eventually the bird should lose interest and move on.
I hope this helps!
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