  We aim at studying the small-scale evolution at the boundaries of an
equatorial coronal hole connected with a channel of open magnetic flux with the
polar region and an `isolated' one in the extreme-ultraviolet spectral range.
We intend to determine the spatial and temporal scale of these changes. Imager
data from TRACE in the Fe IX/X 171 A passband and EIT on-board Solar and
Heliospheric Observatory in the Fe XII 195 A passband were analysed. We found
that small-scale loops known as bright points play an essential role in coronal
holes boundaries evolution at small scales. Their emergence and disappearance
continuously expand or contract coronal holes. The changes appear to be random
on a time scale comparable with the lifetime of the loops seen at these
temperatures. No signature was found for a major energy release during the
evolution of the loops. Although coronal holes seem to maintain their general
shape during a few solar rotations, a closer look at their day-by-day and even
hour-by-hour evolution demonstrates a significant dynamics. The small-scale
loops (10" - 40" and smaller) which are abundant along coronal hole boundaries
have a contribution to the small-scale evolution of coronal holes. Continuous
magnetic reconnection of the open magnetic field lines of the coronal hole and
the closed field lines of the loops in the quiet Sun is more likely to take
place.
