Window bird feeder and stickers

Hello I’m new so I’m not sure if I’m asking in the correct place. Please forgive me if not.

I am interested in buying a rspb window bird feeder for my Mum to enjoy watching the birds from her chair which is much more stimulating than the tv which she is beginning to find difficult following as she has Alzheimer’s, vascular dementia and Parkinsonism. It’s for a single glazed window and I’m wondering if I need to buy the stickers of birds too to stop birds flying into the window around the bird feeder.

Please advise.

thank you very much

kind regards

Catherine Lynne