  We present measurements of the real diagonal microwave conductivity of the
reentrant insulating quantum Hall phases in the first excited Landau level at
temperatures below 50 mK. A resonance is detected around filling factor
$\nu=2.58$ and weaker frequency dependence is seen at $\nu=2.42$ and 2.28.
These measurements are consistent with the formation of a bubble phase crystal
centered around these $\nu$ at very low temperatures.
