  A great burst of cluster formation increased the rate at which open clusters
were formed in the Large Magellanic Cloud 3-5 Gyr ago by at least an order of
magnitude. On the other hand the rate of star formation ~ 4 Gyr appears to have
increased by a factor of only 2-4. This shows that the rate of cluster
formation is not a good tracer of the rate at which stars are formed.
Normalized to the same rate of star formation, the Large Cloud is presently
forming / 600 times more star clusters than the Local Group dwarf irregular IC
1613. The high rate of cluster formation in merging gas-rich galaxies suggests
that strong shocks might favor the formation of clusters.
