Osteology of birds - Shufeldt, Robert Wilson 1850 -1934 (University of the State of New York, 1909)

Osteology of the waterfowl - Woolfenden, Glen Everett, 1930 - (1960)

O.S.U. naturalist - Ohio State University. Biological Club. (Biological Club of Ohio State University, 1901)

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)

Outdoor life in England - Fisher, Arthur T. (R. Bentley and son, 1896)

Over vogels van Deli (Sumatra) - Heyst, A. F. C. A. van (1919)

Pacific coast avifauna - Cooper Ornithological Club. (Cooper Ornithological Club, 1912)

Pacific science - University of Hawaii. (University Press of Hawaii, 1947)

Pacific seabirds : a publication of the Pacific Seabird Group - Pacific Seabird Group. (The Group, 1995)

Paleontological investigations at Mineral Hill Cave - Broughton, Jack M. (U.S. Department of the Interior, Bureau of Land Management, Elko Field Office, 2004)

Pamietnik Fizyjograficzny (Druk K. Kowalewskiego, 1918)

Pamphlets on forestry in Minnesota (1900)

Pamphlets on forestry in West Virginia (1900)

Panama, 1947 : to visit the Canal Zone Biological Area, inspect the San Jose Project of 1944, and collect bird specimens in Darien. Assisted by Watson M. Perrygo. Correspondence, expense records, travel notes, newsclippings, and film notes; Correspondents include John Enos Graf, Of special interest is a letter from Wetmore to H. R. Harmon (12 June 1947) which contains a report on the expedition - Wetmore, Alexander, 1886 -1978 (1947)

Papéis avulsos do Departamento de Zoologia - São Paulo Departamento de Zoologia (A Secretaria, 1948)

Papéis avulsos do Departamento de Zoologia - São Paulo Departamento de Zoologia (A Secretaria, 1952)

Papers from the Hopkins-Stanford Galapagos expedition, 1898-1899 - Hopkins-Stanford Galapagos Expedition, 1898-99. (The Academy, 1901)

Patterns in biodiversity in Arctic birds. WCMC Biodiversity Bulletin No. 3 - Zöckler, Christoph (WCMC, 1998)

P.D. Skaar's Montana bird distribution - Montana Natural Heritage Program. (Montana Natural Heritage Program, 2012)

P.D. Skaar's Montana bird distribution - Bergeron, Dwight. (Montana Natural Heritage Program, 1992)

P.D. Skaar's Montana bird distribution - Skaar, Palmer David. (Montana Natural Heritage Program, 1996)

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)

Perú: Cordillera Escalera-Loreto - Stotz, Douglas F. (Douglas Forrester), 1956 - (The Field Museum, Science and Education, 2014)

Perú, Medio Putumayo-Algodón - Stotz, Douglas F. (Douglas Forrester), 1956 - (Field Museum of Natural History, 2016)

Perú : Tapiche-Blanco - Field Museum of Natural History. (The Field Museum, 2015)

Pesticides documentation bulletin - National Agricultural Library (U.S.) (National Agricultural Library, U.S. Dept. of Agriculture, #c 1965-1969, 1965)

Pfarrer P. Blasius Hanf als Ornitholog. Dargestellt vorzüglich auf Grundlage der Schriften desselben - Schaffer, Alexander. (Im Selbstverlag der Benediktiner-Abtei, 1904)

Pflügers Archiv für die gesamte Physiologie des Menschen und der Tiere (M. Hager, 1911)

Philippine birds - Du Pont, John E. (John Eleuthère), 1938 -2010 ([Delaware Museum of Natural History], 1971)

Photoperiodism and related phenomena in plants and animals; proceedings - Withrow, Robert B. 1904 -1958 (1959)

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

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

Pigeons - Selby, Prideaux John, 1788 -1867 (W. H. Lizars; [etc., etc, 1845)

The Pleistocene avifauna of the Talara tar seeps, northwestern Peru - Campbell, Kenneth E. Jr. (Kenneth Eugene), 1943 - (1973)

Pleistocene birds of the palearctic : a catalogue - Nuttall Ornithological Club. (Nuttall Ornithological Club, 1998)

The polar and tropical worlds : a description of man and nature in the polar and equatorial regions of the globe - Hartwig, G. (Georg), 1813 -1880 (Published by Bill, Nichols & Company, 1872)

The polar and tropical worlds : a popular and scientific description of man and nature in the polar and equatorial regions of the globe : embracing the combined results of all the explorations, researches and discoveries of modern times - Hartwig, G. (Georg), 1813 -1880 (C.A. Nichols, 1876)

The polar and tropical worlds: a description of man and nature in the polar and equatorial regions of the globe - Hartwig, G. (Georg), 1813 -1880 (Johnson & McClain, 1871)

Portraits and habits of our birds - Pearson, T. Gilbert (Thomas Gilbert), 1873 -1943 (National association of Audubon societies, 1921)

Portraits and habits of our birds - Pearson, T. Gilbert (Thomas Gilbert), 1873 -1943 (National Association of Audubon Societies, 1925)

Postilla - Peabody Museum of Natural History. (Peabody Museum of Natural History, 1950)

Postilla - Peabody Museum of Natural History. (Peabody Museum of Natural History, 1962)

Postilla - Peabody Museum of Natural History. (Peabody Museum of Natural History, 1968)

Postilla - Peabody Museum of Natural History. (Peabody Museum of Natural History, 1991)

Praktische Naturgeschichte der Vögel, für Gebildete aller Stände - Reichenbach, A. B. (Anton Benedikt), 1807 -1880 (1850)

A preliminary catalog of the birds of Missouri - Widmann, Otto (Academy of Sciences of St. Louis?, 1907)

A preliminary catalog of the birds of Missouri - Widmann, Otto (Academy of Science of St. Louis, 1907)

A preliminary catalogue of the flowering plants and higher cryptogams growing without cultivation within thirty miles of Hanover, N.H., to which is appended a list of the vertebrates of the same region - Jesup, Henry G. (Henry Griswold), 1826 -1903 (N.A. McClary, 1882)

Preliminary report on the fish and fisheries of Ontario - Wright, R. Ramsay (Robert Ramsay), 1852 -1933 (s.n, 1892)

Primae lineae systematis naturæ : nexui naturali omnium evolutionique progressivae per nixus reascendentes superstructi - Gori͡aninov, Pavel Fedorovich, 1796 -1865 (Typis Karoli Krajanis, 1834)

Principles of animal ecology - Allee, W. C. (Warder Clyde), 1885 -1955 (Saunders Co, 1949)

Problems of genetics - Bateson, William, 1861 -1926 (Yale University Press, 1913)

Problems of genetics - Bateson, William, 1861 -1926 (Yale University Press, 1916)

Problems of genetics - Bateson, William, 1861 -1926 (Yale University Press; [etc., etc.], 1913)

Proceedings - Dorset Natural History; Archaeological Society.

Proceedings - Dorset Natural History and Archaeological Society - Dorset Natural History; Archaeological Society. (1877)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1852)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1866)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1870)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1905)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1913)

Proceedings of the Academy of Natural Sciences of Philadelphia - Academy of Natural Sciences of Philadelphia. (Academy of Natural Sciences of Philadelphia, 1841)

Proceedings of the Belfast Natural History and Philosophical Society - Belfast Natural History; Philosophical Society. (1874)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1917)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1976)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1978)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1987)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1990)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1992)

Proceedings of the Biological Society of Washington - Smithsonian Institution (Biological Society of Washington, 1999)

Proceedings of the Boston Society of Natural History - Boston Society of Natural History. (Boston Society of Natural History, 1848)

Proceedings of the Boston Society of Natural History - Boston Society of Natural History. (Boston Society of Natural History, 1907)

Proceedings of the Bournemouth Natural Science Society - Bournemouth Natural Science Society (1915)

Proceedings of the California Academy of Sciences, 4th series - California Academy of Sciences (California Academy of Sciences, 1962)

Proceedings of the Entomological Society of Washington - Entomological Society of Washington (Entomological Society of Washington, 1979)

Proceedings of the Entomological Society of Washington - Entomological Society of Washington (Entomological Society of Washington, 1980)

Proceedings of the Entomological Society of Washington - Entomological Society of Washington (Entomological Society of Washington, 1981)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1900)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1909)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1908)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1915)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1914)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1916)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1918)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1919)

Proceedings of the Indiana Academy of Science - Indiana Academy of Science. ([s.n.], 1920)

Proceedings of the International Ornithological Congress (Australian Academy of Science [etc.], 1891)

Proceedings of the International Ornithological Congress (Australian Academy of Science [etc.], 1911)

Proceedings of the International Ornithological Congress (Australian Academy of Science [etc.], 1929)

Proceedings of the International Ornithological Congress (Australian Academy of Science [etc.], 1938)

Proceedings of the International Ornithological Congress (Australian Academy of Science [etc.], 1951)