Les oiseaux de l'Europe et leurs oeufs, décrits et dessinés d'après nature - Dubois, Alphonse, 1839 -1921. (chez C. Muquardt, 1872)

Les oiseaux de la province de Que´bec - Dionne, C.-E. (Charles-Eusèbe), 1846 -1925 (Dussault & Proulx, 1906)

Les oiseaux du Canada - Dionne, C.-E. (Charles-Eusèbe), 1846 -1925 (s.n.], 1883)

Les oiseaux du Canada - Dionne, C.-E. (Charles-Eusèbe), 1846 -1925 (P. G. Delisle, 1883)

Les oiseaux - Perrier, Edmond, 1844 -1921 (J.B. Bailli, 1904)

Oiseaux - Fédération des sociétés françaises de sciences naturelles. Office central de faunistique. (P. Lechevalier, 1921)

Okens Lehrbuch der Naturgeschichte - Oken, Lorenz, 1779 -1851 (Bei Carl Heinrich Reclam, 1815)

Okens Lehrbuch der Naturgeschichte - Oken, Lorenz, 1779 -1851 (Bei Carl Heinrich Reclam, 1816)

Oldman River Dam ... raptor mitigation program - Alberta. Alberta Environment. (Govt. of the Province of Alberta, Dept. of Public Works, Supply and Services, 1990)

Oldman River Dam ... raptor mitigation program - Alberta. Alberta Environment. (Govt. of the Province of Alberta, Dept. of Public Works, Supply and Services, 1991)

On a collection of birds from North-Eastern Abyssinia and the Bogos Country - Jesse, William. (Zoological Society of London, 1870)

On the anatomy of vertebrates - Owen, Richard, 1804 -1892 (Longmans, Green, 1866)

On the anatomy of vertebrates ... - Owen, Richard, 1804 -1892 (Longmans, Green and Co, 1866)

On the birds of the islands of Aruba, Curaçao, and Bonaire - Hartert, Ernst, 1859 -1933 (s.n, 1893)

On the distribution of birds in Great Britain, during the nesting season - More, Alexander Goodman, 1830 -1895 (British Ornithologists' Union, 1865)

On the geology and natural history of the upper Missouri :Being the substance of a report made to Lieut. G.K. Warren, T.E. U.S.A - Hayden, F. V. (Ferdinand Vandeveer), 1829 -1887 (Printed by C. Sherman & son, 1862)

On the natural history and classification of birds - Swainson, William, 1789 -1855 (John Taylor, 1836)

On the Natural History and classification of Birds : vol. I and II - Swainson, William, 1789 -1855 (pr. for Longman [etc.], 1836)

On the power, wisdom, and goodness of God : as manifested in the creation of animals, and in their history, habits, and instincts - Jones, Thomas Rymer, 1810 -1880 (H.G. Bohn, 1853)

On the power, wisdom and goodness of God, as manifested in the creation of animals, and in their history, habits and instincts - Kirby, William, 1759 -1850 (Carey, Lea & Blanchard, 1836)

On the power, wisdom and goodness of God as manifested in the creation of animals and in their history, habits and instincts - Kirby, William, 1759 -1850 (W. Pickering, 1835)

Onomasticon zoicon, plerorumque animalium differentias & nomina propria pluribus linguis exponens : cui accedunt Mantissa anatomica, et quaedam De variis fossilium generibus - Charleton, Walter, 1619 -1707 (Apud Jacobum Allestry ..., 1668)

Onze vogels in huis en tuin - Keulemans, J. G. (John Gerrard), 1842 -1912 (P.W.M. Trap, 1869)

The oölogist's record (Harrison and Sons, 1921)

The oölogist's record (Harrison and Sons, 1922)

Oologia neerlandica : eggs of birds breeding in the Netherlands - Lechner, Arnold Anthon van Pelt (Nijhoff, 1911)

Ootheca Wolleyana: an illustrated catalogue of the collection of birds' eggs - Newton, Alfred, 1829 -1907 (sold by R. H. Porter, 1905)

Opera ornithologica - Bonaparte, Charles-Lucien, 1803 -1857 (1857)

Opinions and declarations rendered by the International Commission on Zoological Nomenclature - International Commission on Zoological Nomenclature (Printed by order of the International Trust for Zoological Nomenclature, 1947)

Opinions and declarations rendered by the International Commission on Zoological Nomenclature - International Commission on Zoological Nomenclature (Printed by order of the International Trust for Zoological Nomenclature, 1939)

Opinions and declarations rendered by the International Commission on Zoological Nomenclature - International Commission on Zoological Nomenclature (Printed by order of the International Trust for Zoological Nomenclature, 1958)

Opinions and declarations rendered by the International Commission on Zoological Nomenclature - International Commission on Zoological Nomenclature (Printed by order of the International Trust for Zoological Nomenclature, 1955)

Opinions and declarations rendered by the International Commission on Zoological Nomenclature - International Commission on Zoological Nomenclature (Printed by order of the International Trust for Zoological Nomenclature, 1956)

Opuscula ornithologica : notis et addendis, mss - Coues, Elliott, 1842 -1899 (1861)

Ordnance survey of the county of Londonderry - Great Britain. Ordnance Survey. (1835)

The Oregon naturalist (Naturalist Pub. Co, 1895)

L'Organisation du Règne animal Oiseaux - Blanchard, Emile, 1819 -1900 (Chez l'Auteur)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1885)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1886)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1887)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1888)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1889)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1890)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1891)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1895)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1896)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1898)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1899)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1904)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1903)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1910)

Ornis - International Ornithological Committee. (Carl Gerold's Sohn, 1905)

Ornis Carinthiae. Die Vögel Kärntens. Verzeichniss der bis jetzt in Kärnten beobachteten Vögel, nebst bemerkungen über deren zug, Lebensweise, locale Eigenthümlichkeiten etc. etc - Keller, Franz Carl, 1847 -1907 (Druck von Ferd. v. Kleinmayr, 1890)

Ornis Caucasica. Die Vogelwelt des Kaukasus : systematisch und biologisch-geographisch beschrieben - Radde, Gustav, 1831 -1903 (Verlag von Theodor Fischer, 1884)

Ornithologia methodice digesta, atque iconibus aeneis ad vivum illuminatis ornata - Lorenzi, Lorenzo. (In Aedibus Mouchianis, 1767)

Ornithologia methodice digesta, atque iconibus aeneis ad vivum illuminatis ornata - Lorenzi, Lorenzo. (In Aedibus Mouchianis, 1773)

Ornithologia, or, The birds: a poem, in two parts : with an introduction to their natural history; and copious notes - Jennings, James. (Sherwood, Gilbert, and Piper, 1829)

Ornithologia, sive, Synopsis methodica sistens avium divisionem in ordines, sectiones, genera, species, ipsarumque varietates : cum brevi & accurata cujusque speciei descriptione, citationibus auctorum de iis tractantium, nominibus eis ab ipsis impositis, nominibusque vulgaribus - Brisson, Mathurin-Jacques, 1723 -1806 (Apud Theodorum Haak, 1763)

Ornithologia Svecica - Nilsson, Sven, 1787 -1883 (Apud J.H. Schubothium, 1821)

Ornithological bibliography - Coues, Elliott, 1842 -1899 (Geological Survey [etc.], 1878)

Ornithological biography, or an account of the habits of the birds of the United States of America ; accompanied by descriptions of the objects represented in the work entitled The Birds of America, and interspersed with delineations of American scenery and manners - Audubon, John James, 1785 -1851 (Adam Black, 1835)