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, 1816)

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

On the fauna and flora of the west of Scotland. Meeting at Glasgow, September, 1876 - British Association for the Advancement of Science. (Blackie, 1876)

On the mental qualities of birds, as compared with their cerebral development - MacGillivray, John, 1821 -1867 (Adam and Charles Black, 1824)

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)

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

The oologists' hand-book : 1885 catalogue of American birds' eggs, and oological supplies, with prices at which they may be obtained of - Lattin, Frank H. (Frank Haak), 1861 -1937 (John P. Smith, Printer, 1885)

Ootheca Wolleyana: an illustrated catalogue of the collection of birds' eggs - Newton, Alfred, 1829 -1907 (sold by R. H. Porter, 1864)

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, 1916)

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)

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, 1891)

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

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)

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

The ornithological guide - Wood, Charles Thorold. (Whittaker, 1835)

An ornithological index, arranged according to the synopsis avium of Mr. Vigors / by T. B. L. Baker - Vigors, N. A.‏ ‎ (Nicholas Aylward),‏ ‎ 1785 -1840 (Printed by R. Taylor, 1835)

[Ornithological papers] - Seebohm, Henry, 1832 -1895 (1876)

Ornithological synonyms - Strickland, Catherine Dorcas Maule Jardine (J. Van Voorst, 1855)

Ornithologie du Canada. D'après la nomenclature de Baird - Le Moine, J. M. Sir, (James MacPherson), 1825 -1912 (Atelier typ. de J.T. Brousseau, 1861)

Ornithologie du Canada quelques groupes d'après la nomenclature du Smithsonian Institution, de Washington - Le Moine, J. M. Sir, (James MacPherson), 1825 -1912 (s.n.], 1860)

Ornithologie européenne, ou, Catalogue descriptif, analytique et raisonné des oiseaux observés en Europe - Gerbe, Zéphirin, 1810 -1890 (J.B. Bailli, 1867)

Ornithologie européenne, ou Catalogue analytique et raisonné des oiseux observés en Europe - Degland, Côme Damien, 1787 -1856 (Roret; [etc., etc.], 1849)

Der Ornithologische Beobachter - Ala, Schweizerische Gesellschaft für Vogelkunde und Vogelschutz. (Ala, Schweizerische Gesellschaft für Vogelkunde und Vogelschutz, 1906)

Ornithologische Briefe : Bla¨tter der Erinnerung an seine Freunde - Homeyer, Eugen Ferdinand von, 1809 -1889 (T. Grieben, 1881)

Ornithologische Monatsberichte (Verlag von R. Friedländer & Sohn, 1895)

Ornithologische Monatsberichte (Verlag von R. Friedländer & Sohn, 1898)

Ornithologische Monatsberichte (Verlag von R. Friedländer & Sohn, 1899)

Ornithologische Monatsberichte (Verlag von R. Friedländer & Sohn, 1906)

Ornithologische Monatsberichte (Verlag von R. Friedländer & Sohn, 1909)

Ornithologische Monatsberichte (Verlag von R. Friedländer & Sohn, 1910)

Ornithologische Monatsberichte (Verlag von R. Friedländer & Sohn, 1893)

Ornithologische Monatsschrift - Deutscher Verein zum Schutze der Vogelwelt. (Kommissions-Verlag der Creutschen Verlagsbuchhandlung, 1891)

Ornithologische Monatsschrift - Deutscher Verein zum Schutze der Vogelwelt. (Kommissions-Verlag der Creutschen Verlagsbuchhandlung, 1899)

Ornithologische Monatsschrift - Deutscher Verein zum Schutze der Vogelwelt. (Kommissions-Verlag der Creutschen Verlagsbuchhandlung, 1904)

Ornithologische Monatsschrift - Deutscher Verein zum Schutze der Vogelwelt. (Kommissions-Verlag der Creutschen Verlagsbuchhandlung, 1905)

Ornithologische Monatsschrift - Deutscher Verein zum Schutze der Vogelwelt. (Kommissions-Verlag der Creutschen Verlagsbuchhandlung, 1906)

Ornithologische Monatsschrift - Deutscher Verein zum Schutze der Vogelwelt. (Kommissions-Verlag der Creutschen Verlagsbuchhandlung, 1908)

Ornithologisches Centralblatt (L.A. Kittler, 1876)

Ornithologisches Jahrbuch (V. Tschusi, 1890)

Ornithologisches Jahrbuch (V. Tschusi, 1896)

Ornithologisches Jahrbuch (V. Tschusi, 1905)

Ornithologisches Jahrbuch (V. Tschusi, 1909)

Ornithologisches Jahrbuch (V. Tschusi, 1914)

Ornithologisches Jahrbuch (V. Tschusi, 1915)

The Ornithologist and oölogist (1889)

The Ornithologist and oölogist (1890)

The ornithologist's text-book : being reviews of ornithological works : with an appendix, containing discussions on various topics of interest - Wood, Neville. (John W. Parker, 1836)

Ornithology - Jardine, William, 1800 -1874 (W.H. Lizars, 1853)

Ornithology and oo¨logy of New England: containing full descriptions of the birds of New England, and adjoining states and provinces - Samuels, Edward A. (Edward Augustus), 1836 -1908 (Nichols and Noyes, 1867)

Ornithology and oölogy of New England: containing full descriptions of the birds of New England, and adjoining states and provinces ... - Samuels, Edward A. (Edward Augustus), 1836 -1908 (Nichols and Noyes, 1867)

Ornithology and oölogy of New England containing full descriptions of the birds of New England and adjoining states and provinces, arranged by a long-approved classification and nomenclature : together with a complete history of their habits, times of arrival and departure ... : with illustrations of many species of the birds and accurate figures of their eggs - Samuels, Edward A. (Edward Augustus), 1836 -1908 (Nichols and Noyes, 1867)

Ornithology - Geological Survey of California. (University press] pub. by authority of the Legislature [of California], 1870)

The ornithology of Illinois - Ridgway, Robert, 1850 -1929 (H.W. Rokker, printer, 1889)

The ornithology of Illinois - Ridgway, Robert, 1850 -1929 (H. W. Rokker, printer, 1889)

Ornitologia italiana : opera postuma - Savi, Paul, 1798 -1871 (Successori Le Monnier, 1873)

Ornitologia toscana; ossia, Descrizione e storia degli uccelli che trovansi nella Toscana, con l'aggiunta della descrizioni di tutti gli altri proprj al rimanente d'Italia - Savi, Paul, 1798 -1871 (Dalla tipografia Nistri, 1827)

L'Ornitologo Ticinese ossia manuale descrittivo gli Uccelli di stazione e di passaggio nel Cantone Ticino, &c - Riva, Antonio. (1865)

Osteology of Circus hudsonius - Shufeldt, Robert Wilson 1850 -1934 (1889)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1891)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1899)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1910)

Our birds of prey; or The eagles, hawks, and owls of Canada. With 30 photographic illus - Vennor, Henry G. (Henry George), 1840 -1884 (Dawson Brothers, 1876)

Our birds of prey, or, The eagles, hawks, and owls of Canada - Vennor, Henry G. (Henry George), 1840 -1884 (Dawson, 1876)

Our birds of prey; or, The eagles, hawks and owls of Canada - Vennor, Henry G. (Henry George), 1840 -1884 (Dawson, 1876)

Our country's birds and how to know them. A guide to all the birds of Great Britain - Gordon, W. J. (Simpkin, Marshall, Hamilton, Kent, 1892)

Our living world; an artistic edition of the Rev. J. G. Wood's Natural history of animate creation - Wood, J. G. (John George), 1827 -1889 (S. Hess, 1885)

Our northern and eastern birds : containing descriptions of the birds of the northern and eastern states and British provinces; together with a history of their habits, times of arrival and departure, their distribution, food, song, time of breeding, and a careful and accurate description of their nests and eggs - Samuels, Edward A. (Edward Augustus), 1836 -1908 (R. Worthington, 1883)

Our northern and eastern birds. Containing descriptions of the birds of the northern and eastern states and British provinces; together with a history of their habits, times of arrival and departure, their distribution, food, song, time of breeding, and a careful and accurate description of their nests and eggs ... - Samuels, Edward A. (Edward Augustus), 1836 -1908 (R. Worthington, 1883)

Our northern and eastern birds containing descriptions of the birds of the northern and eastern states and British provinces, together with a history of their habits, times of arrival and departure, their distribution, food, song, time of breeding, and a careful and accurate description of their nests and eggs ; with illustrations of many species of the birds and accurate figures of their eggs - Samuels, Edward A. (Edward Augustus), 1836 -1908 (R. Worthington, 1883)

Our winter birds - Trent, Mary, Mrs. (1882)

Outlines of a natural arrangement of the Falconidae - Ridgway, Robert, 1850 -1929 (Govt. Print. Off, 1875)

Outlines of American ornithology : part 1, Land birds - Baird, Spencer Fullerton, 1823 -1887 (Little, Brown, 1873)

Oversigt af Christiania omegns ornithologiske fauna - Collett, Robert, 1842 -1913 (J. Dahl, 1864)

Los pájaros insectívoros, bajo el punto de vista agricola - Lemée, Cárlos. (J. Sesé, 1909)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1918)

Papers and communications read before the Natural History Society of British Columbia - Natural History Society of British Columbia. (Natural History Society of British Columbia?], 1891)

Papers and proceedings of the Royal Society of Tasmania - Royal Society of Tasmania. (The Society, 1890)

Pennsylvania bird life; a manual of the birds of Pennsylvania; treating especially of their food, from examinations of several thousand stomachs, made during all seasons of the year, with descriptions of the birds, their nests, eggs and habits - Warren, Benjamin Harry, 1858 -1926 (Penn'a., Pub by the author, 1892)

Philosophical transactions of the Royal Society of London - Royal Society (Great Britain) (Royal Society of London, 1879)

The pictorial museum of animated nature ... - Knight, Charles, 1791 -1873 (C. Knight, 1844)

The pictorial museum of animated nature - William Clowes; Sons, (George Cox, 18 King Street, Covent Garden, 1844)

Planches coloriees des oiseaux de la Belgique et de leurs oeufs - Dubois, Ch. F. (Charles Frédéric), 1804 -1867 (C. Muquardt, 1854)

Pocket key of the birds of the northern United States, east of the Rocky Mountains - Apgar, A. C. (Austin Craig), 1838 -1908 (J.L. Murphy Pub. Co., Printers, 1893)

A popular handbook of the birds of Canada and the United States - Nuttall, Thomas, 1786 -1859 (Musson Book Co, 1907)

A popular handbook of the birds of the United States and Canada - Nuttall, Thomas, 1786 -1859 (Little, Brown, 1903)