This data set describes the phylogenetic relationships of the families
of birds as reported by Sibley and Ahlquist (1990). Sibley and
Ahlquist inferred this phylogeny from an extensive number of DNA/DNA
hybridization experiments. The ``tapestry'' reported by these two
authors (more than 1000 species out of the ca. 9000 extant bird
species) generated a lot of debates.
The present tree is based on the relationships among families. A few
families were not included in the figures in Sibley and Ahlquist, and
thus are not included here as well. The branch lengths were calculated
from the values of \(\Delta T_{50}H\) as found in Sibley
and Ahlquist (1990, figs. 354, 355, 356, and 369).