I realise that I had mis-remembered this. It is primarily bat deaths that are caused by the air pressure changes around turbines - not birds. This is because bats have a particularly large and thin lung internal membranes which gives them high efficiency. The rapid decompression in the immediate wake of the turbine blades - particularly towards the tips, which are the fastest moving part of course - damages this membrane.

Birds have more compact lungs and hollow bones which aid in their breathing - a different solution to the efficiency problem and one that is not as susceptible to these pressure changes.