Air Rifle Hunting Dirty Pigeons have To Go

I was asked by a farmer friend to help with a problem he has with feral pigeons and jackdaws coming into his sheds and as well as scrounging not only through the silage but also the feed bins for meal that's given to the cattle they were dunging all over the shed and his machinery. This can cause not only a health and safety issue for the livestock but also those who work in the sheds as the birds dung over everything, the silage, water troughs, bars, gates, walls and even the cattle.
This is all done on farm land that i have permission to do so on with legally held air rifles and is done in a legal and humane manner as not to prolong or glorify the death of the birds.
This can legally be done through the Department Of Agriculture, Environment And Rural Affairs Wildlife (Northern Ireland) Order 1985 (As Amended) Licence.
This Licence hereby authorises for the purpose of preventing the spread of disease and preventing serious damage to livestock, foodstuffs for livestock, crops, vegetables, fruit, growing timber and fisheries ANY AUTHORISED PERSON to kill or take any of the following birds:-
Crow, Jackdaw, Magpie, Pigeon (Wood), Pigeon (Feral), Rook, Sparrow (House), Starling.
Range Finder Bushnell Scout 1000
Equifix Dutch Bay
Tactacam 5.0 and FTS unit
Rifle BSA Super10 John Bowkett Blueprinted .22cal 15ft/lb
Scope Nikko Stirling Targetmaster 4-16x44 LRX
Pellets JSB Diabolo Exact 15.9 Grain