  Fifty-seven nearby low surface brightness dwarf galaxies were searched for
globular cluster candidates (GCCs) using Hubble Space Telescope WFPC2 imaging
in V and I. The sample consists of 18 dwarf spheroidal (dSph), 36 irregular
(dIrr), and 3 "transition" type (dIrr/dSph) galaxies with angular sizes less
than 3.7 kpc situated at distances 2-6 Mpc in the field and in the nearby
groups: M81, Centaurus A, Sculptor, Canes Venatici I cloud. We find that ~50%
of dSph, dIrr/dSph, and dIrr galaxies contain GCCs. The fraction of GCCs
located near the center of dwarf spheroidal galaxies is >2 times higher than
that for dIrrs. The mean integral color of GCCs in dSphs, V-I = 1.04+/-0.16
mag, coincides with the corresponding value for Galactic globular clusters and
is similar to the blue globular cluster sub-populations in massive early-type
galaxies. The color distribution for GCCs in dIrrs shows a clear bimodality
with peaks near V-I = 0.5 and 1.0 mag. Blue GCCs are presumably young with ages
t < 1 Gyr, while the red GCC population is likely to be older. The detected
GCCs have absolute visual magnitudes between M_V = -10 and -5 mag. We find
indications for an excess population of faint GCCs with M_V > -6.5 mag in both
dSph and dIrr galaxies, reminiscent of excess populations of faint globular
clusters in nearby Local Group spiral galaxies. The measurement of structural
parameters using King-profile fitting reveals that most GCCs have structural
parameters similar to extended outer halo globular clusters in the Milky Way
and M31, as well as the recently discovered population of "faint fuzzy"
clusters in nearby lenticular galaxies.
