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, 1913)

The ornithology of Illinois - Ridgway, Robert, 1850 -1929 (H.W. Rokker, printer, 1885)

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)

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)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1889)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1896)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1898)

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

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1900)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1901)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1902)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1905)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1915)

The Ottawa naturalist - Ottawa Field-Naturalists' Club (Ottawa Field-Naturalists' Club, 1917)

Our birds in their haunts : a popular treatise on the birds of eastern North America - Langille, J. H. (James Hibbert), 1841 -1923 (Orange Judd, 1892)

Our feathered game; a handbook of the North American game birds - Huntington, Dwight W. (Dwight Williams), 1851 -1938 (C. Scribner's Sons, 1911)

Our feathered game : a handbook of the North American game birds - Huntington, Dwight W. (Dwight Williams), 1851 -1938 (C. Scribner's Sons, 1911)

Our feathered game; a handbook of the North American game birds - Huntington, Dwight W. (Dwight Williams), 1851 -1938 (C. Scribner's Sons, 1903)

Our living resources : a report to the nation on the distribution, abundance, and health of U.S. plants, animals, and ecosystems - United States. National Biological Service. (U.S. Dept. of the Interior, National Biological Service, 1995)

Pacific coast avifauna - Cooper Ornithological Club. (Cooper Ornithological Club, 1902)

Pacific coast avifauna - Cooper Ornithological Club. (Cooper Ornithological Club, 1915)

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

Pacific seabirds : a publication of the Pacific Seabird Group - Pacific Seabird Group. (The Group, 1997)

Pacific seabirds : a publication of the Pacific Seabird Group - Pacific Seabird Group. (The Group, 1998)

Pacific seabirds : a publication of the Pacific Seabird Group - Pacific Seabird Group. (The Group, 2012)

Palaeontology - Palaeontological Association (Palaeontological Association, 1988)

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)

Part I. Palæontology - Hall, James, 1811 -1898 (Govt. print. off, 1877)

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

Paxton's Botanical dictionary; comprising the names, history, and culture of all plants known in Britain; with a full explanation of technical terms. New ed. including all the new plants up to the present year - Paxton, Joseph, Sir, 1803 -1865 (Bradbury, Evans, & co, 1868)

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, 2003)

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)

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

Phytoneuron (Guy L. Nesom, 2012)

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

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

Plumas Lassen Study : 2006 annual report - Sierra Nevada Research Center (U.S.) (USDA Forest Service Pacific Southwest Research Station, Sierra Nevada Research Center, 2006)

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)

Polar bear foraging behavior during the ice-free period in western Hudson Bay : observations, origins, and potential significance - Rockwell, Robert F. (American Museum of Natural History, 2017)

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)

A popular handbook of the birds of the United States and Canada - Nuttall, Thomas, 1786 -1859 (Little, Brown, 1905)

A popular handbook of the birds of the United States and Canada - Nuttall, Thomas, 1786 -1859 (Little, Brown, 1921)

A popular handbook of the birds of the United States and Canada - Nuttall, Thomas, 1786 -1859 (Little, Brown, 1919)

A popular handbook of the ornithology of eastern North America - Nuttall, Thomas, 1786 -1859 (Little, Brown, 1891)

A popular Handbook of the Ornithology of Eastern North America - Nuttall, Thomas, 1786 -1859 (Truslove and Hanson, 1894)

A popular handbook of the ornithology of eastern North America - Nuttall, Thomas, 1786 -1859 (Little, Brown, and Company, 1896)

A popular handbook of the ornithology of the United States and Canada, based on Nuttall's Manual - Nuttall, Thomas, 1786 -1859 (Little, Brown, and Company, 1891)

Popular natural history : a description of animal life, from the lowest forms up to man - Kingsley, J. S. (John Sterling), 1854 -1929 (Estes & Lauriat, 1890)

A practical handbook of British birds - Witherby, H. F. (Harry Forbes), 1873 -1944 (Witherby, 1924)

A practical handbook of British birds - Witherby, H. F. (Harry Forbes), 1873 -1944 (Witherby, 1921)

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

A preliminary catalog of the birds of Missouri - Widmann, Otto (Academy of Sciences 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)

A preliminary list of the birds found in Vermont - Perkins, George H. (George Henry), 1844 -1933 (Wynkoop Hallenbeck Crawford Co, 1901)

A preliminary list of the birds of Jones Beach, Long Island, N.Y - Linnaean Society of New York (Linnaean Society of New York, 1935)

A preliminary list of the birds of Wayne County, Ohio - Oberholser, Harry C. (Harry Church), 1870 -1963 (Westbote Co., State Printers, 1896)

Preliminary note on the taxonomy of Canada geese, Branta canadensis - Delacour, Jean, 1890 -1985 (American Museum of Natural History, 1951)

A preliminary report on the biology of Harding County, northwestern South Dakota - Visher, Stephen Sargent, 1887 -1967 (State Publishing Co, 1914)

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

Proceedings and transactions of the Nova Scotian Institute of Natural Science - Nova Scotian Institute of Natural Science. (Nova Scotian Institute of Natural Science, 1879)

Proceedings and transactions of the Nova Scotian Institute of Natural Science - Nova Scotian Institute of Natural Science. (Nova Scotian Institute of Natural Science, 1886)

Proceedings and transactions of the Texas Academy of Science - Texas Academy of Science. (The Academy, 1945)

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