  Let $G$ be a non-elementary word-hyperbolic group acting as a convergence
group on a compact metrizable space $Z$ so that there exists a continuous
$G$-equivariant map $i:\partial G\to Z$, which we call a \emph{Cannon-Thurston
map}. We obtain two characterzations (a dynamical one and a geometric one) of
conical limit points in $Z$ in terms of their pre-images under the
Cannon-Thurston map $i$. As an application we prove, under the extra assumption
that the action of $G$ on $Z$ has no accidental parabolics, that if the map $i$
is not injective then there exists a non-conical limit point $z\in Z$ with
$|i^{-1}(z)|=1$. This result applies to most natural contexts where the
Cannon-Thurston map is known to exist, including subgroups of word-hyperbolic
groups and Kleinian representations of surface groups. As another application,
we prove that if $G$ is a non-elementary torsion-free word-hyperbolic group
then there exists $x\in \partial G$ such that $x$ is not a "controlled
concentration point" for the action of $G$ on $\partial G$.
