Von der Decken's hornbill (Tockus deckeni) is named after the German explorer Baron Karl Klaus von der Decken (1833–1865). It is found in East Africa, especially to the east of the East African Rift, from Ethiopia south to Tanzania. It is found mainly in thorn scrub and similar arid habitats. Von der Decken’s hornbills maintain year-round pair bonds that can last for a decade or more. A new partner is chosen only when one of the birds dies. These hornbills communicate their sex and age through differences in bill colour. Juveniles and adult females sport shorter, solid black bills, while adult males have longer, yellow bills with bright orange bases. Like all hornbills, von der Decken’s are hole-nesters, using natural cavities in trees or rock crevices. But unlike other hole-nesters, female hornbills use mud and feces to make a brick-hard seal over the cavity opening, leaving only a narrow slit through which she and her chicks receive food from her mate. While inside the nest hole, a female von der Decken’s hornbill sheds all her flight and tail feathers and grows a full set of sleek new feathers.