  We have previously shown that the decay of high-energy neutrinos from distant
astrophysical sources would be revealed by flavor ratios that deviate strongly
from the $\phi_{\nu_e}:\phi_{\nu_\mu}:\phi_{\nu_\tau} = 1:1:1$ expected from
oscillations alone. Here we show that the deviations are significantly larger
when the mixing angle $\theta_{13}$ and the CP phase $\delta$ are allowed to be
nonzero. If neutrinos decay, this could allow measurement of $\theta_{13}$ and
$\delta$ in IceCube and other near-term neutrino telescopes.
