  We interpret the recent observation of a zero-bias anomaly in spin-1 quantum
dots in terms of an underscreened Kondo effect. Although a spin-1 quantum dots
are expected to undergo a two-stage quenching effect, in practice the log
normal distribution of Kondo temperatures leads to a broad temperature region
dominated by underscreened Kondo physics. General arguments, based on the
asymptotic decoupling between the partially screened moment and the leads,
predict a singular temperature and voltage dependence of the conductance $G$
and differential conductance $g$, resulting in $dg/dT\sim 1/T$ and $dG/dV \sim
1/V$. Using a Schwinger boson approach, we show how these qualitative
expectations are borne out in a detailed many body calculation.
