The number given above does actually represent the number of birds axed by the blades. The footprint for each 2.1 megawatt turbine is typically 10 x 10 metres. That means it takes 10,000 towers to spoil 1 square kilometre for bird breeding.
Access roads for the towers take up a great deal more, of course, but wind farms are usually built inside a farmer's field or a pastoralist's pasture in exchange for an annual fee. The land is already deforested. Fields and pastures are not particularly suitable environments for birds to breed on. The shills are just waffling a load of bullshit, as usual.
Then there is the spacing required between the units. It would leave a lot of opportunity for birds to breed if the land were suitable for the task to begin with. Check it out here. This is part of the Snowtown wind farm I drive past every time I travel to Adelaide.