Attracting birds to a 1st floor flat

Hi all,

I have been trying to feed the birds local to me for a few months now, first using a window feeder full of a seed mix and some dried mealworms. It initially took a few weeks for any birds to find or trust it, but it did get some interest (only when my curtains were closed). I had quite a lot of visitors yesterday morning (mostly house sparrows) so I figured it was time to upgrade my setup. I bought a seed feeder and attached it to my balcony railing, and I bought some new food for the window feeder. This included silkworm pupae, dried grasshoppers, black soldier fly. I also put dried mealworms and the original seed mix in the feeder.

I've had not one bird visit the feeder today. Why is this? Will it take another few weeks for birds to trust the new food? I just assumed because they were loving the window feeder already that they'd keep coming back.

I'm no expert, so please let me know if I'm doing something wrong!

Any advice appreciated, thank you