  Aims: To gain better insight on the physics of stripped-envelope
core-collapse supernovae through studying their environments. Methods: We
obtained low-resolution optical spectroscopy with the New Technology Telescope
(+ EFOSC2) at the locations of 20 Type Ib/c supernovae. We measure the flux of
emission lines in the stellar-continuum-subtracted spectra from which local
metallicities are computed. For the supernova regions we estimate both the mean
stellar age, interpreting the stellar absorption with population synthesis
models, and the age of the youngest stellar populations using the H-alpha
equivalent width as an age indicator. These estimates are compared with the
lifetimes of single massive stars. Results: Based on our sample, we detect a
tentative indication that Type Ic supernovae might explode in environments that
are more metal-rich than those of Type Ib supernovae (average difference of
0.08 dex), but this is not a statistically significant result. The lower limits
placed on the ages of the supernova birthplaces are overall young, although
there are several cases where these appear older than what is expected for the
evolution of single stars more massive than 25-30 M_{sun}. This is only true,
however, assuming that the supernova progenitors were born during an
instantaneous (not continuous) episode of star formation. Conclusions: These
results do not conclusively favor any of the two evolutionary paths (single or
binary) leading to stripped supernovae. We do note a fraction of events for
which binary evolution is more likely, due to their associated age limits. The
fact, however, that the supernova environments contain areas of recent (< 15
Myr) star formation and that the environmental metallicities are, at least, not
against the single evolutionary scenario, suggest that this channel is also
broadly consistent with the observations.
