Packard's school essays, written while at Canton High School from 1875 to 1879, describe his daily activities and aspirations and discuss various themes of morality, politics, history, and nature.

Packard's largely undated manuscripts consist of nonfiction articles that he submitted to various publishers, often including the publishers' letters of acceptance or rejection. Subjects included nature, birds, and maritime themes.

This subseries consists of Packard's typewritten manuscript for his book, He Dropped into Poetry, which he self-published in 1940.

This subseries consists of typed and handwritten copies of various poems written by Packard.

Included are files containing article drafts and notes by subject, as arranged by Packard. The bulk of his "Nature" drafts were used as a basis for his Boston Evening Transcript articles. His "Personal file" includes book notes and ideas, a dramatic script, and poetry.

Packard's index consists of a series of notecards listing individual drafts by subject, as reflected in Subseries E, Drafts. The index is not comprehensive.

The earlier commonplace-book contains poems and essays copied by Packard's mother, Maria Blake Packard, from 1854 to 1880. Brief entries by Packard include a line-a-day journal discussing the weather and his daily activities as a twelve-year-old boy from 1-21 January 1875; a "Diary of Birds' Nests" containing sporadic entries about nests and their locations, written from April 1875 to May 1879; and an undated fictional manuscript. The 1894 commonplace-book is a small folio of copied poems, most likely in Packard's hand.

Packard's memo books largely consist of small notebooks of about 40 pages containing dated entries, as well as other nature observations, sketches, and accounts. His thirteen memo books written between 1882 and 1884 describe his life in Canton and in Boston as a student at the Massachusetts Institute of Technology. He also discusses a July 1882 voyage to Gloucester, with descriptions of the town and its fishermen; the 8 April 1883 fire at the Hotel Berkeley in Boston; and his summer in Newport, Rhode Island, with descriptions of the town in June and July 1883. The notebooks primarily contain Packard's descriptions of birds and nature, his social activities, landscape sketches, poems, and observations of daily life. The 24-31 July 1882 memo book uses racist imagery and language to describe African Americans picnicking on Boston's India Wharf.

The "Greenhouse diary," which Packard compiled between 1890 and 1892, contains descriptions of his flowers and vegetables, gardening activities, greenhouse maintenance and repairs, and accounts of plants sold.

Packard's Spanish-American War diary, written from May to September 1898, describes his tour of duty with the second division of the Massachusetts Naval Reserve, including the blockade of Havana. He discusses life aboard the U.S.S. Prairie, an auxiliary cruiser; the ship's movements and activities; and views of Florida, Guantanamo, San Juan, and Haiti. The notebook is written in pencil and is in poor condition.

Packard's 1911 and 1922 memo books are largely nature journals in which he describes the flora and fauna of Maine and New Hampshire. He used much of this material for his articles in the Boston Evening Transcript. Packard's 1928 notebook describes his cruise from New York to Florida, the Caribbean, Costa Rica, and Panama. His 1931 notebook contains brief information about his trips to Puerto Rico and Florida. An undated notebook includes Packard's brief description of a trip to Ireland, largely discussing its buildings and vegetation.

This subseries contains copies of published juvenile fiction, nonfiction articles, and poetry written by Winthrop Packard. The bulk of nonfiction articles are newspaper clippings of Packard's column in the Boston Evening Transcript on subjects including birds, nature, maritime history, ships, fisheries, political opinion, Alaska, and Santo Domingo, Dominican Republic.

This subseries includes a "literary miscellany" of newspaper clippings saved by Packard; review clippings for Packard's book The Young Ice Whalers (1903); miscellaneous notices and reviews for Packard's books; material related to his Puerto Rico trip in 1931, including maps, brochures, and several Puerto Rican magazines; copies of The Florida Naturalist, published by the Florida Audubon Society (1934-1936); a map of the southwestern United States; and several undated copies of Packard's "Everything for Wild Birds" catalogs.