  Coronal upflows at the edges of active regions (AR), which are a possible
source of slow solar wind, have been found to connect with dynamics in the
transition region. To infer at what scale transition region dynamics connect to
AR upflows, we investigate the statistical properties of the small-scale
dynamics in the transition region underneath the upflows at the edge of AR NOAA
11934. With observations from the Interface Region Imaging Spectragraph (IRIS),
we found that the Si IV 1403\,\AA\ Doppler map consists of numerous
blue-shifted and red-shifted patches mostly with sizes less than 1\,$Mm^2$. The
blue-shifted structures in the transition region tend to be brighter than the
red-shifted ones, but their nonthermal velocities have no significant
difference. With the SWAMIS feature tracking procedure, in IRIS slit-jaw
1400\,\AA\ images we found that dynamic bright dots with an average size of
about 0.3\,$Mm^2$ and lifetimes mostly less than 200\,s spread all over the
region. Most of the bright dots appear to be localised, without clear signature
of propagation of plasma to a long distance on the projection plane. Surge-like
motions with speeds about 15 km/s could be seen in some events at the
boundaries of the upflow region, where the magnetic field appear to be
inclined. We conclude that the transition region dynamics connecting to coronal
upflows should occur in very fine scale, suggesting that the corresponding
coronal upflows should also be highly-structured. It is also plausible that the
transition region dynamics might just act as stimulation at the coronal base
that then drives the upflows in the corona.
