The information you locate from a variety of contributors appears to show that there is definitely a problem with bird mortality and wind energy. At the same time, the wind power industry, private-sector institutions, public-sector institutions and scholars are working on ways to lessen the impact. Also, the potential danger to animal life from wind-power appears to pale in comparison to the danger posed to ALL life from other forms of energy generation (climate change due to rising CO2 levels, strip coal mining, fracking, oil pipeline construction through wildlife habitat, deep water oil drilling, etc.).
You would want to be sure that your message strategy does not minimize the harm to birds, but also points out the efforts being taken by the industry to address the problems with newer technologies, additional precautions, changes in turbine sitings (offshore rather than on land), compliance with existing and emerging regulations and related initiatives.
The message strategy you might propose to your Executive Director would include recommendations to include these types of arguments, with plenty of links and references to the information and evidence you have located, in any public comments, website content, news releases, “talking points” documents, and related messages to address the immediate “crisis” and to address longer-term communication needs for the association.