1492 – Columbus discovers the new world and European settlement follows. Bald ea-gles are common and wide ranging across the continent in regions with aquatic habi-tats. An estimated 100,000 bald eagles inhabit what will become the lower 48 states.
1600s – In keeping with cultural traditions, the Delaware people trap and kill eagles to obtain feathers to wear as adornments and for use in tribal ceremonies. American Indian tribes regard the eagle and its feathers as sacred.
1681 – King Charles II grants William Penn his colony in North America. Settlers find a land of seemingly inexhaustible natural resources. In Penn's Woods, eagles nest in low densities along rivers and streams and the forested shorelines of natural lakes.
1782 – America adopts the bald eagle as the na-tional bird and symbol. The Second Continental Congress uses the image of the bald eagle to cre-ate the Great Seal of the United States.
1792 – The Lands Act motivates people to move westward and waves of emigrants, speculators and pioneers begin spreading west and north across Pennsylvania. These settlers clear forests for homesteads and alter habitats along the way.
1800s - Like other large predators, eagles be-come reputed among farmers, hunters, fishermen and other citizens as marauders and killers that will deplete fish and game resources and jeopard-ize livestock. By the mid to late 1800s, along with the bald eagle many predators decline. Some are even eradicated. During this time, shorebirds, wa-terfowl and game birds also dwindle from the loss of habitat and inadequate resource management.
1830s – Railroad speculators receive construction contracts to expand railroads throughout the state. This opens transportation beyond rivers, canals and stagecoaches to aid industrial growth. Expanding railroads also enable market hunting to thrive.
1841- Several Pennsylvania counties begin to adopt statutes protecting certain song-birds, particularly insect-eating birds.
1895 – Pennsylvania Game Commission is created to conserve and restore habitat and manage wild game resources.
1918 – The bald eagle is one of about 800 bird species to gain protection under new federal regulations in the form of the Migratory Bird Treaty Act of 1918.
1920 – The timber boom that began in the latter half of the 19th century continues until Pennsylvania forests are all but depleted. During this same period, mining for coal reaches its peak. Other minerals are mined as well. Entire mountainsides are clear-cut with logging or stripped and scraped for coal and minerals. Rivers and streams are heavily polluted. The environmental impact affects all wildlife dependent on healthy wa-terways and forest land.
1934 – Conservation advocate, Rosalie Edge, leases a series of rock outcrops atop Hawk Mountain, a site notorious for gunners systematically shooting migrating raptors for sport and market. This 1,400-acre property on the Kittatinny Ridge becomes the world's first sanctuary for birds of prey.
1934 – U.S. Migratory Bird Hunting Stamp debuted. Revenue it raises will help pur-chase thousands of wetland acres that benefit waterfowl and bald eagles.
1940 – The Bald Eagle Protection Act prohibits any form of hunting, possession or sale of bald eagles, including eagle parts, nests and eggs.
1940s – Production of synthetic pesticides for agriculture increases and insecticides such as DDT are widely used across the United States to control insect pests in the ag-riculture industry.
1950s – The federal government begins regulating the use of DDT after years of repeated warnings from scientists who believe that cer-tain environmental hazards are related to DDT.
1960 – The National Audubon Society initiates the Continental Bald Eagle Project, which reveals a decline in bald eagle populations be-lieved caused by reproductive failure.
1962 – Silent Spring is published. The New York Times best-selling ecology book by Rachel Carson documents the devastating effects of pesticides on birds and the environment. The book triggers strong public reaction and prompts stronger environmental legislation.
1963 – Only 417 eagle pairs nest in the lower 48 states.
1965 – Clean Streams Act begins to right water pollution problems caused by acid mine drainage. Leads to improved aquatic resources.
1966 – The Endangered Species Preservation Act authorizes the Secretary of the Interior to list endangered fish and wildlife species. A pro-vision of the act allocates funds for the U.S. Fish and Wildlife Service (USFWS) to purchase land for the preservation of habitats crucial to the listed species.
1967 – The bald eagle is on the brink of extinction and is listed as a federally endangered species under the Endangered Species Preserva-tion Act across the United States in all areas below the 40th parallel north.
1972 – The Environmental Protection Agency bans DDT in the United States.
1973 – The Endangered Species Act is signed into law.
1977 – Clean Water Act approved; further improves water quality and restore biodiversity in the nation's waterways.
1978 – The USFWS lists the bald eagle as endangered throughout the lower 48 states with the exception of five states where it is declared threatened.
1983 – Bald eagles are nearly extirpated in Pennsylvania. Just three pairs of eagles nest in the northwest region of the state. In June, the Game Commission's Eagle Re-covery Project Team departs for Laronge, Saskatchewan, to capture young eagles and transfer them back to Pennsylvania. It is the first of seven such missions.
1987 – U.S. Fish & Wildlife Service calls for nationwide ban on lead shot in waterfowl hunting. All states must comply by 1991. Pennsylvania banned lead shot for water-fowl hunting in 1988. Eagles were susceptible to secon-dary poisoning by consuming crippled or dead waterfowl harboring lead shot.
1988 – An eagle's nest is discovered in Tioga County, marking the first nest in the eastern half of the state in decades.
1989 – Eight known nests in Pennsylvania produce five eaglets. The breeding birds are hacked eagles from Penn-sylvania's reintroduction efforts and from similar restora-tion projects in neighboring states.
1996- The bald eagle's federal status is upgraded to threatened.
1999 – Forty-three active nests produce 47 eaglets, the most dramatic nesting popu-lation increase yet.
2006 – Of the 101 known eagle pairs nesting in Pennsylvania, 172 young eagles are fledged.
2007 – The U.S. Fish and Wildlife Service removes the bald eagle from the federal en-dangered species list. The bald eagle remains threatened in Pennsylvania and continues to be protected under state and federal laws.
2009 – Bald eagles nest in 48 Pennsylvania counties. These nests produce a record of at least 244 eaglets.
2010 – There were 197 territorial nesting pairs observed in Pennsylvania. The nesting population exceeded 100 pairs for fifth consecutive year. Nests produced a record of at least 293 young, the second time the state's nests produced more than 200 eaglets.
2011 – Many Pennsylvanians enjoy the opportunity to watch bald eagles. The bald ea-gle's continued recovery largely depends on conservation measures to improve and maintain water quality throughout Pennsylvania and to protect the forest habitat bor-dering its river systems.
By Kathy Korber and Doug Gross