What kind of feeder is suitable for larger birds?

Many smaller birds are attracted to the feeder I bought from the R.S.P.B.  It has the Pigeon tray at the bottom too, and that gets used by the smaller birds as well.     

However, we have regular visits from a blackbird and another one which I think may be a blackbird too (i'ts dark brown - is that a female?)  They never show interest in the feeders but go for seeds on the ground.  Originally these were from feeder spillage, but now I put some on the ground myself.

Why don't the blackbird/s use the feeders, and what can I provide for them?

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