Comparative biology of owls. Evolution and classification of North American owls
Comparative ecology and distribution
Comparative morphology and physiology
Comparative reproductive biology
Natural histories of North American owls. Family Tytonidae. Barn owl
Family Strigidae. Flammulated owl
Appendix 1: Key to genera and species of North American owls (exclusive of strictly Mexican species)
Key to genera and species of indigenous Mexican owls
Key to structural variations in external ears of North American owl genera (exclusive of Mexico)
Appendix 2: Advertisement and other typical calls of non-Mexican North American owls
Appendix 3: Origins of scientific and vernacular names of North American owls.
