Both the Rodrigues solitaire and the dodo are now extinct. A common threshold of the extinction of the dodo is 1662, but some possible sightings had been made as late as 1688. The last sighting with a description was in 1662, but a statistical analysis by Roberts and Solow found that the extinction of the dodo was in 1693. The Rodrigues solitaire was killed off later than the dodo. The IUCN uses an extinction date of 1778 for the solitaire, although a more probable date would be in the 1750s or 1760s. Both birds became extinct as a consequence of human hunting and the introduction of mammals that ate the birds and their eggs.