I have an aviary and a dove cote in my garden which unfortunately come within the territory of a Sparrowhawk. It has been coming into the garden and taking the occasional bird for the last couple of years. Anyway about 6 weeks ago we lost 3 doves in one week, one of them was handreared and had just hatched chicks one of which died. I was really upset and knowing the hawk would come back to the carcass hid in my garden intending to scare it off by shouting and waving my arms at it. I waited and sure enough after about 30 mins it returned and after perching in the garden and calling for a couple of minutes it spotting me, sat and watched me then launched itself at me in my small alley way hiding space, needless to say it way me who went for cover. so I looked for a better way to protect my doves and found the Portek Hawkeyes scare, you can see photo's and read a proper review at Steve the duck blog I hope you find it as helpful as I have in protecting my doves
Protecting Doves from Sparrowhawks
Protecting Doves from Sparrowhawks