  Level densities and radiative strength functions in $^{171}$Yb and $^{170}$Yb
nuclei have been measured using the
$^{171}$Yb($^3$He,$^3$He$^\prime\gamma$)$^{171}$Yb and
$^{171}$Yb($^3$He,$\alpha\gamma$)$^{170}$Yb reactions. New data on $^{171}$Yb
are compared to a previous measurement for $^{171}$Yb from the
$^{172}$Yb($^3$He,$\alpha\gamma$)$^{171}$Yb reaction. Systematics of level
densities and radiative strength functions in $^{170,171,172}$Yb are
established. The entropy excess in $^{171}$Yb relative to the even-even nuclei
$^{170,172}$Yb due to the unpaired neutron quasiparticle is found to be
approximately 2$k_B$. Results for the radiative strength function from the two
reactions lead to consistent parameters characterizing the ``pygmy''
resonances. Pygmy resonances in the $^{170,172}$Yb populated by the
($^3$He,$\alpha$) reaction appear to be split into two components for both of
which a complete set of resonance parameters are obtained.
