Thornapple. Datura sp. Rather poisonous too.

Not likely from the feeder.

Do I just kill it with weed killer ?

Or pull it out, if there are just a few.

Datura stramonium, Thorn-apple. It's an American plant and can be found in bird seed mixes. It does pop up in gardens now and then.

Hmm...never imagined that it would be found in bird seeds, but birds would be far less affected by the alkaloids than mammals.

One of the reasons why plant poisons do not affect birds where they do affect humans, is that birds lack an enzyme which interacts with the poison in the fruit. Thus blackbirds can eat Aronia berries which contain cyanide where a human could not.

I think the Thorn-apples are pretty, we get them popping up in various places - they do seed well! Every so often you get a scare-mongering report in the local newspaper about a dangerous, alien, poisonous plant appearing from nowhere! It's always this and providing you don't go round eating plants found in the garden - why worry? After all we grow loads of plants that are poisonous! We get Redwings that come in later in the year and eat the berries on the Yew tree which I always thought were deadly, proving a point Owdboggy! Mind you we had a Peacock who died of eating something (vet didn't know what) and we thought it was wild Bryony, which though pretty is also poisonous to humans.