What do you put in this kind of bird seed feeder?

[JustJam4Tea]

Peanuts, suet balls? Seed will just fall-out...

I would say peanuts. The holes may allow a bit of the convex sides of the peanut to show proud and give access for pecking. Not seen one like that before though.

peanuts is probably a good shout...

Suet pellets? Never seen a feeder like that. Not even sure what kind of bird would hang upside down with no perch

Weird. Nothing for them to land on or hold on to.

See - I must have bought it for a reason - but found it when clearing out the cupboards and just can't remember....

@JustJam4Tea

See - I must have bought it for a reason - but found it when clearing out the cupboards and just can't remember....

I'm thinking there is a bit missing from it. I just can't work out how the birds are going to get at the food otherwise.

Agree try peanuts in it. Titmice will hand upside down to get to the peanuts. I wonder if it was sold as squirrel or pigeon proof or some such thing? (it wouldn't be squirrel proof as they will just chew the plastic..)

I would think it's for peanuts and aimed at the tits, who hang upside down to feed.

I'll try peanuts. There might be a bit missing - have a vague memory of a tray of some kind...