Figures show the number of wind patent awards fell to 146 during the three-month period, 24 fewer than a year earlier, and five lower than the previous quarter.
The granting of patents by the US Patent and Trademark Office is often regarded as a gauge for the levels of research and development in which the industry is engaged.
GE and Mitsubishi, which just settled a five-year US patent dispute, were the leaders in terms of the number of wind-related patents granted. Mitsubishi just edged its rival, with 19 patents awarded, compared with GE's 16.
The number of solar patents clearly outstripped those for wind, with 225 granted over the period, which correlates with solar's much more rapid fall in its levelised cost of energy.
This data seems to run counter to claims by some experts that the industry is experiencing a period of growth in research and development after a period of contraction as a result of the economic crash.
However, with the average US patent taking two years to process, it could be that a recovery in applications is yet to be shown in the figures for the granting of patents.