Weir, J.T., and Schluter, D. 2008. Calibrating the avian molecular clock. Molecular Ecology 17(10):2321-2328. doi: 10.1111/j.1365-294X.2008.03742.x.
ABSTRACT: Molecular clocks are widely used to date phylogenetic events, yet
evidence supporting the rate constancy of molecular clocks through time and
across taxonomic lineages is weak. Here, we present 90 candidate avian clock
calibrations obtained from fossils and biogeographical events.