  We construct a cocycle that, for a given $n$-manifold, maps pairs of
asymptotically locally hyperbolic (ALH) metrics to a tractor-valued
$(n-1)$-form field on the conformal infinity. This requires the metrics to be
asymptotically related to a given order that depends on the dimension. It then
provides a local geometric quantity on the boundary that is naturally
associated to the pair and can be interpreted as a relative energy-momentum
density. It is distinguished as a geometric object by its property of being
invariant under suitable diffeomorphisms fixing the boundary, and that act on
(either) one of the argument metrics. Specialising to the case of an ALH metric
$h$ that is suitably asymptotically related to a locally hyperbolic conformally
compact metric, we show that the cocycle determines an absolute invariant
$c(h)$, which still is local in nature. This tractor-valued $(n-1)$-form field
on the conformal infinity is canonically associated to $h$ (i.e. is not
dependent on other choices) and is equivariant under the appropriate
diffeomorphisms. Finally specialising further to the case that the boundary is
a sphere and that a metric $h$ is asymptotically related to a hyperbolic metric
on the interior, we show that the invariant $c(h)$ can be integrated over the
boundary. The result pairs with solutions of the KID (Killing initial data)
equation to recover the known description of hyperbolic mass integrals of Wang,
and Chru\'{s}ciel--Herzlich.
