Why do phylogenomic data sets yield conflicting trees? Data type influences the avian tree of life more than taxon sampling

Sushma Reddy, Rebecca T. Kimball, Akanksha Pandey, Peter A. Hosner, Michael J. Braun, Shannon J. Hackett, Kin Lan Han, John Harshman, Christopher J. Huddleston, Sarah Kingston, Ben D. Marks, Kathleen J. Miglia, William S. Moore, Frederick H. Sheldon, Christopher C. Witt, Tamaki Yuri, Edward L. Braun^*