Question: What is the military branch of the person being the president when the US state from which bar-tailed godwits migrate was purchased?

full_context: Document 1: Reconstruction era: As Confederate states came back under control of the U.S. Army, President Abraham Lincoln set up reconstructed governments in Tennessee, Arkansas, and Louisiana during the war. He experimented by giving land to blacks in South Carolina. By fall 1865, the new President Andrew Johnson declared the war goals of national unity and the ending of slavery achieved and reconstruction completed. Republicans in Congress, refusing to accept Johnson's lenient terms, rejected new members of Congress, some of whom had been high - ranking Confederate officials a few months before. Johnson broke with the Republicans after vetoing two key bills that supported the Freedmen's Bureau and provided federal civil rights to the freedmen. The 1866 Congressional elections turned on the issue of Reconstruction, producing a sweeping Republican victory in the North, and providing the Radical Republicans with sufficient control of Congress to override Johnson's vetoes and commence their own ``Radical Reconstruction ''in 1867. That same year, Congress removed civilian governments in the South, and placed the former Confederacy under the rule of the U.S. Army. The army conducted new elections in which the freed slaves could vote, while whites who had held leading positions under the Confederacy were temporarily denied the vote and were not permitted to run for office.
Document 2: Alaska Purchase: The Alaska Purchase (Russian: Продажа Аляски, tr. Prodazha Alyaski) was the United States' acquisition of Alaska from the Russian Empire on March 30, 1867, by a treaty ratified by the United States Senate, and signed by President Andrew Johnson.
Document 3: Bird migration: Some bar-tailed godwits Limosa lapponica have the longest known non-stop flight of any migrant, flying 11,000 km from Alaska to their New Zealand non-breeding areas. Prior to migration, 55 percent of their bodyweight is stored as fat to fuel this uninterrupted journey.
Document 4: John Aaron Rawlins: John Aaron Rawlins (February 13, 1831 September 6, 1869) was a general officer in the Union Army during the American Civil War and a cabinet officer in the Grant administration. A longtime confidant of Ulysses S. Grant, Rawlins served on Grant's staff throughout the war, rising to the rank of brevet major general, and was Grant's chief defender against allegations of insobriety. He was appointed Secretary of War when Grant was elected President of the United States.
Document 5: Alaska Purchase: Russia continued to see an opportunity to weaken British power by causing British Columbia, including the Royal Navy base at Esquimalt, to be surrounded or annexed by American territory. Following the Union victory in the civil war, the Tsar instructed the Russian minister to the United States, Eduard de Stoeckl, to re-enter into negotiations with William Seward in the beginning of March 1867. President Johnson was entangled in negotiations about Reconstruction and Seward had alienated a number of Republicans, so they believed that the purchase would help divert attention from the current domestic matters. The negotiations concluded after an all - night session with the signing of the treaty at 04: 00 on March 30, 1867, with the purchase price set at $7.2 million ($123 million today), or about 2 cents per acre ($4.74 / km).
Document 6: Catharinus P. Buckingham: Catharinus Putnam Buckingham (March 14, 1808 – August 30, 1888) was an American soldier, college professor, author, and industrialist. He served as a general in the Union Army during the American Civil War, and was the main assistant to the U.S. Secretary of War, Edwin M. Stanton, during part of the first term of the Lincoln Administration.
Document 7: Bird migration: Bird migration is not limited to birds that can fly. Most species of penguin (Spheniscidae) migrate by swimming. These routes can cover over 1,000 km (620 mi). Dusky grouse Dendragapus obscurus perform altitudinal migration mostly by walking. Emus Dromaius novaehollandiae in Australia have been observed to undertake long-distance movements on foot during droughts.
Document 8: Bird migration: The same considerations about barriers and detours that apply to long-distance land-bird migration apply to water birds, but in reverse: a large area of land without bodies of water that offer feeding sites may also be a barrier to a bird that feeds in coastal waters. Detours avoiding such barriers are observed: for example, brent geese Branta bernicla migrating from the Taymyr Peninsula to the Wadden Sea travel via the White Sea coast and the Baltic Sea rather than directly across the Arctic Ocean and northern Scandinavia.
Document 9: Lafayette C. Baker: Lafayette Curry Baker (October 13, 1826 – July 3, 1868) was a United States investigator and spy, serving the Union Army, during the American Civil War and under Presidents Abraham Lincoln and Andrew Johnson.
Document 10: Alaska Purchase: The Alaska Purchase (Russian: Продажа Аляски, tr. Prodazha Alyaski) was the United States' acquisition of Alaska from the Russian Empire on March 30, 1867, by a treaty ratified by the United States Senate, and signed by president Andrew Johnson.
Document 11: Lincoln (novel): Set during the American Civil War, the novel describes the presidency of Abraham Lincoln through the eyes of several historical figures, including presidential secretary John Hay, First Lady Mary Todd Lincoln, Secretary of State William H. Seward, Secretary of the Treasury Salmon Chase, his daughter Kate Chase, U.S. Representative Elihu B. Washburne, and conspirators John Wilkes Booth and David Herold.
Document 12: Department of Alaska: The Department of Alaska was the designation for the government of Alaska from its purchase by the United States of America in 1867 until its organization as the District of Alaska in 1884. During the department era, Alaska was variously under the jurisdiction of the U.S. Army (until 1877), the U.S. Dept. of the Treasury (from 1877 until 1879) and the U.S. Navy (from 1879 until 1884). The area later became the District of Alaska, then the Territory of Alaska, then the State of Alaska.
Document 13: Bird migration: Seabird migration is similar in pattern to those of the waders and waterfowl. Some, such as the black guillemot Cepphus grylle and some gulls, are quite sedentary; others, such as most terns and auks breeding in the temperate northern hemisphere, move varying distances south in the northern winter. The Arctic tern Sterna paradisaea has the longest-distance migration of any bird, and sees more daylight than any other, moving from its Arctic breeding grounds to the Antarctic non-breeding areas. One Arctic tern, ringed (banded) as a chick on the Farne Islands off the British east coast, reached Melbourne, Australia in just three months from fledging, a sea journey of over 22,000 km (14,000 mi). Many tubenosed birds breed in the southern hemisphere and migrate north in the southern winter.
Document 14: Bird migration: The Arctic tern holds the long-distance migration record for birds, travelling between Arctic breeding grounds and the Antarctic each year. Some species of tubenoses (Procellariiformes) such as albatrosses circle the earth, flying over the southern oceans, while others such as Manx shearwaters migrate 14,000 km (8,700 mi) between their northern breeding grounds and the southern ocean. Shorter migrations are common, including altitudinal migrations on mountains such as the Andes and Himalayas.
Document 15: Alaska Purchase: Russia continued to see an opportunity to weaken British power by causing British Columbia, including the Royal Navy base at Esquimalt, to be surrounded or annexed by American territory. Following the Union victory in the Civil War, the Tsar instructed the Russian minister to the United States, Eduard de Stoeckl, to re-enter into negotiations with William H. Seward in the beginning of March 1867. President Johnson was entangled in negotiations about Reconstruction and Seward had alienated a number of Republicans, so they believed that the purchase would help divert attention from the domestic issues. The negotiations concluded after an all - night session with the signing of the treaty at 04: 00 on March 30, 1867, with the purchase price set at $7.2 million ($105 million in 2016), or about 2 cents per acre ($4.74 / km).
ground_truth: Union Army
sub_queries: Where do bar-tailed godwits migrate from Answer: Alaska
who was the president when Alaska was purchased Answer: Andrew Johnson
Andrew Johnson >> military branch Answer: Union Army