  Starting from the assumption that there is a large population (> 10^8) of
isolated, stellar-mass black holes (IBH) distributed throughout our galaxy, we
consider the detectable signatures of accretion from the interstellar medium
(ISM) that may be associated with such a population. We simulate the nearby
(radius 250 pc) part of this population, corresponding to the closest ~35 000
black holes, using current best estimates of the mass distribution of stellar
mass black holes combined with two models for the velocity distribution of
stellar-mass IBH which bracket likely possibilities. We distribute this
population of objects appropriately within the different phases of the ISM and
calculate the Bondi-Hoyle accretion rate, modified by a further dimensionless
efficiency parameter \lambda. Assuming a simple prescription for radiatively
inefficient accretion at low Eddington ratios, we calculate the X-ray
luminosity of these objects, and similarly estimate the radio luminosity from
relations found empirically for black holes accreting at low rates. The latter
assumption depends crucially on whether or not the IBH accrete from the ISM in
a manner which is axisymmetric enough to produce jets. Comparing the predicted
X-ray fluxes with limits from hard X-ray surveys, we conclude that either the
Bondi-Hoyle efficiency parameter \lambda, is rather small (< 0.01), the
velocities of the IBH are rather high, or some combination of both. The
predicted radio flux densities correspond to a population of objects which,
while below current survey limits, should be detectable with the Square
Kilometre Array (SKA). Converting the simulated space velocities into proper
motions, we further demonstrate that such IBH could be identified as faint high
proper motion radio sources in SKA surveys.
