Feeding birds in Communal gardens - help/advice needed!

I have been feeding the birds in our communal gardens of the flats I live in for some time. One of my neighbours is a bit of a bully and has complained about this and 2 general letters have been sent out to all and now I have one directed specifically at me. The argument being that I am littering the communal gardens & attracting vermin ie rats & mice – which if I thought I as I would stop straight away but I don’t believe this to be the case. Please note I only put good quality bird food and I put a small amount on the wooden fence posts, my window sill and a small amount on the ground for the sparrows who are ground feeders but not all over the communal gardens so don’t know how this can constitute littering. Further the main Kings Cross North East Line runs at the back of the flats and yes we have had rats in the past (sure we still do) but I don't believe this is anything to do with me and the boxes of poison put down by the bin area seem to control them to a point. I would also point out that some individuals leave bags with food spilling out all over the bin area - I have pictures and reported this to the Management Agents and NO communication was sent out about this - surely this is more of a hazard than what I am doing! Also a lot of the other owner/residents and the renters all seem to enjoy the wild birds and have commented on how stupid these letters are and how they enjoy the birds. Plus I know I am not breaking the law. However the letter I received today, states: "We hope that by bringing this to your attention we will be able to avoid any further action being taken" Now what this action will be I have no idea. NB. I have checked the lease and there is no specific clause about this but a couple that do seem a bit grey in definition. Would be happy to post these clauses if somebody has any legal knowledge. I don’t want to get into an argument with this neighbour but for the past 11 years I have allowed him to park his motor bike/pedal bikes in my covered off street car park space and I was going to ask him remove but my husband said don’t be spiteful but after this latest letter I am so upset with him – especially as he seems to think that I am not aware that it is him complaining and continues to use my parking! Also my immediate neighbour now rents out his flat because this individual complained so much about noise made by him and his family that he could not take it anymore and moved out! It seems this chap wants a fight with somebody and now it is my turn. Can somebody help me? Can they stop me doing something that brings pleasure to all? How should I respond – I have left a message for the person who sent the letter to call me back but nothing so far. When I previously spoke to the Agents in January – I was told by our property manager - that it was fine for me to carry on but just be careful – since then he has left and we have a new manager. Previous manager also told me that the complainant was very demanding to deal with! Thanks for any help you can give me.