Peter G. Kaestner is an American diplomat and amateur ornithologist currently serving as a senior inspector in the Office of Inspector General of the U.S. State Department. From 2006 to 2009 he was the consul general of the American Embassy in New Delhi, India. As consul general, he oversaw consular operations in New Delhi and the U.S. Consulates Generals in Mumbai (Bombay), Chennai (Madras), Hyderabad, and Kolkata (Calcultta).
Born in Baltimore, Maryland,in 1953 to Benjamin Henry Kaestner, Sr. and Alice (Reed) Kaestner, he is the middle child of 10 siblings and step-siblings. After spending two years in the Peace Corps in Zaire, Kaestner entered the Foreign Service in 1981, and has been assigned in the past to India, Egypt, Brazil, Guatemala, New Guinea, the Solomon Islands, Colombia, Malaysia, and Namibia. In 1990 he had his first child with his wife Kimberly Vreeland Kaestner, Katherine Kaestner. In 1991 the couple had a second child, Laurel Kaestner.
An avid birder, he has taken advantage of his position as an international diplomat to follow his hobby more avidly than is normally possible. By 1986, he had become the first birder to see a representative of each bird family in the world, though the list of bird families recognized by science has changed considerably since then.
In 1989, while on a birding expedition in Colombia, he discovered a species new to science, the Cundinamarca Antpitta (Grallaria kaestneri). (See Formicariidae.) With a life list above 8,200 birds, Kaestner remains one of the most prolific birders in the world, surpassed only by very few, such as Hugh Buck and Jon Hornbuckle and the late Phoebe Snetsinger.