From Scientific American an interesting article about birds and dodos too: Bird Extinction Estimates May Be Too Low.
Since 1500, more than 150 bird species have disappeared from the world, including the much lamented dodo. This ground bird disappeared from its island home before Carl Linnaeus, the father of scientific taxonomy, even described it in the 18th century. Given that many of the nearly 10,000 known bird species have only recently been described–including those only available from remains like the dodo–some biologists suggest that current extinction rates have been seriously underestimated and will rise rapidly in the coming century.
Stuart Pimm of Duke University and his colleagues analyzed current estimates of bird extinction rates. Out of 9,975 known bird species, 154 have disappeared, or roughly 1.3 percent. Extrapolated, this yields an estimate of 26 extinctions per million bird species every year. Based on fossil records, scientists estimate that normal extinction rates average just one lost animal for every million species per year.
Read the whole article here.