  The flow of shape eigenmodes of the small fluctuation operator around BPS
2-vortex solutions is calculated, as a function of the intervortex separation
$2d$. For the rotationally-invariant 2-vortex, with $d = 0$, there are three
discrete modes; the lowest is non-degenerate and the upper two are degenerate.
As $d$ increases, the degeneracy splits, with one eigenvalue increasing and
entering the continuous spectrum, and the other decreasing and asymptotically
coalescing with the lowest eigenvalue, where they jointly become the eigenvalue
of the 1-vortex radial shape mode. The behaviour of the eigenvalues near $d=0$
is clarified using a perturbative analysis, and also in light of the 2-vortex
moduli space geometry.
