Brood parasites are organisms that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own, using brood mimicry, for example by having eggs that resemble the host's (egg mimicry).
Brood parasitism relieves the parasitic parents from the investment of rearing young or building nests for the young, enabling them to spend more time on other activities such as foraging and producing further offspring. Bird parasite species mitigate the risk of egg loss by distributing eggs amongst a number of different hosts. As this behaviour damages the host, it often results in an evolutionary arms race between parasite and host as the pair of species coevolve.
The strength of defenses and counter-adaptation rely on the host/parasitic species' ability to evolve; some host species have very strong rejection defenses resulting in the parasitic species evolving to have very close mimicry. In other species, hosts do not show rejection defenses and as a result, the parasitic species will show no evolved trait (example: egg mimicry).
A chicken can be hypnotized, or put into a trance, by holding its head down against the ground, and drawing a line along the ground with a stick or a finger, starting at the beak and extending straight outward in front of the chicken. If the chicken is hypnotized in this manner, it will continue to stare at the line, remaining immobile for as long as 30 minutes. Other methods of inducing this state are also known. Ethologists refer to this state as 'tonic immobility' i.e. a natural state of semi-paralysis that some animals enter when presented with a threat, which is probably a defensive mechanism intended to feign death, albeit rather poorly.
The first known written reference for this method came in 1646, in Mirabele Experimentum de Imaginatione Gallinae by Athanasius Kircher in Rome.
Mike the Headless Chicken (April 20, 1945 – March 17, 1947), also known as Miracle Mike, was a Wyandotte chicken that lived for 18 months after his head had been cut off. Although the story was thought by many to be a hoax, the bird's owner took him to the University of Utah in Salt Lake City to establish the facts.
- "Mike the Headless Chicken" | 2015-11-11 | 52 Upvotes 14 Comments
Pigeon photography is an aerial photography technique invented in 1907 by the German apothecary Julius Neubronner, who also used pigeons to deliver medications. A homing pigeon was fitted with an aluminium breast harness to which a lightweight time-delayed miniature camera could be attached. Neubronner's German patent application was initially rejected, but was granted in December 1908 after he produced authenticated photographs taken by his pigeons. He publicized the technique at the 1909 Dresden International Photographic Exhibition, and sold some images as postcards at the Frankfurt International Aviation Exhibition and at the 1910 and 1911 Paris Air Shows.
Initially, the military potential of pigeon photography for aerial reconnaissance appeared interesting. Battlefield tests in World War I provided encouraging results, but the ancillary technology of mobile dovecotes for messenger pigeons had the greatest impact. Owing to the rapid perfection of aviation during the war, military interest in pigeon photography faded and Neubronner abandoned his experiments. The idea was briefly resurrected in the 1930s by a Swiss clockmaker, and reportedly also by the German and French militaries. Although war pigeons were deployed extensively during World War II, it is unclear to what extent, if any, birds were involved in aerial reconnaissance. The United States Central Intelligence Agency (CIA) later developed a battery-powered camera designed for espionage pigeon photography; details of its use remain classified.
The construction of sufficiently small and light cameras with a timer mechanism, and the training and handling of the birds to carry the necessary loads, presented major challenges, as did the limited control over the pigeons' position, orientation and speed when the photographs were being taken. In 2004, the British Broadcasting Corporation (BBC) used miniature television cameras attached to falcons and goshawks to obtain live footage, and today some researchers, enthusiasts and artists similarly deploy crittercams with various species of animals.
- "Pigeon photography" | 2014-07-17 | 79 Upvotes 11 Comments
Tromelin Island (; French: Île Tromelin, pronounced [il tʁɔmlɛ̃]) is a low, flat island in the Indian Ocean about 500 kilometres (310 mi) north of Réunion and about 450 kilometres (280 mi) east of Madagascar. Tromelin is administered as part of the French Southern and Antarctic Lands, a French Overseas Territory, but Mauritius claims sovereignty over the island.
Tromelin has facilities for scientific expeditions and a weather station. It is a nesting site for birds and green sea turtles.
Alex (May 1976 – 6 September 2007) was a grey parrot and the subject of a thirty-year experiment by animal psychologist Irene Pepperberg, initially at the University of Arizona and later at Harvard University and Brandeis University. When Alex was about one year old, Pepperberg bought him at a pet shop. The name Alex was an acronym for avian language experiment, or avian learning experiment. He was compared to Albert Einstein and at two years old was correctly answering questions made for six-year-olds.
Before Pepperberg's work with Alex, it was widely believed in the scientific community that a large primate brain was needed to handle complex problems related to language and understanding; birds were not considered to be intelligent, as their only common use of communication was mimicking and repeating sounds to interact with each other. However, Alex's accomplishments supported the idea that birds may be able to reason on a basic level and use words creatively. Pepperberg wrote that Alex's intelligence was on a level similar to dolphins and great apes. She also reported that Alex seemed to show the intelligence of a five-year-old human, in some respects, and he had not even reached his full potential by the time he died. She believed that he possessed the emotional level of a two-year-old human at the time of his death.
- "Alex" | 2021-07-09 | 17 Upvotes 1 Comments
The term Pfeilstorch (German for "arrow stork") is given to storks injured by an arrow while wintering in Africa, before returning to Europe with the arrow stuck in their bodies. To date, around 25 Pfeilstörche have been documented.
The first and most famous Pfeilstorch was a white stork found in 1822 near the German village of Klütz, in the state of Mecklenburg-Vorpommern. It was carrying a 30-inch (76 cm) spear from central Africa in its neck. The specimen was stuffed and can be seen today in the zoological collection of the University of Rostock. It is therefore referred to as the Rostocker Pfeilstorch.
This Pfeilstorch was crucial in understanding the migration of European birds. Before migration was understood, people struggled to explain the sudden annual disappearance of birds like the white stork and barn swallow. Besides migration, some theories of the time held that they turned into other kinds of birds, mice, or hibernated underwater during the winter, and such theories were even propagated by zoologists of the time. The Rostocker Pfeilstorch in particular proved that birds migrate long distances to wintering grounds.
The great auk (Pinguinus impennis) is a species of flightless alcid that became extinct in the mid-19th century. It was the only modern species in the genus Pinguinus. It is not closely related to the birds now known as penguins, which were discovered later by Europeans and so named by sailors because of their physical resemblance to the great auk.
It bred on rocky, remote islands with easy access to the ocean and a plentiful food supply, a rarity in nature that provided only a few breeding sites for the great auks. When not breeding, they spent their time foraging in the waters of the North Atlantic, ranging as far south as northern Spain and along the coastlines of Canada, Greenland, Iceland, the Faroe Islands, Norway, Ireland, and Great Britain.
The great auk was 75 to 85 centimetres (30 to 33 inches) tall and weighed about 5 kilograms (11 pounds), making it the largest alcid to survive into the modern era, and the second-largest member of the alcid family overall (the prehistoric Miomancalla was larger). It had a black back and a white belly. The black beak was heavy and hooked, with grooves on its surface. During summer, great auk plumage showed a white patch over each eye. During winter, the great auk lost these patches, instead developing a white band stretching between the eyes. The wings were only 15 cm (6 in) long, rendering the bird flightless. Instead, the great auk was a powerful swimmer, a trait that it used in hunting. Its favourite prey were fish, including Atlantic menhaden and capelin, and crustaceans. Although agile in the water, it was clumsy on land. Great auk pairs mated for life. They nested in extremely dense and social colonies, laying one egg on bare rock. The egg was white with variable brown marbling. Both parents participated in the incubation of the egg for around 6 weeks before the young hatched. The young left the nest site after 2–3 weeks, although the parents continued to care for it.
The great auk was an important part of many Native American cultures, both as a food source and as a symbolic item. Many Maritime Archaic people were buried with great auk bones. One burial discovered included someone covered by more than 200 great auk beaks, which are presumed to be the remnants of a cloak made of great auks' skins. Early European explorers to the Americas used the great auk as a convenient food source or as fishing bait, reducing its numbers. The bird's down was in high demand in Europe, a factor that largely eliminated the European populations by the mid-16th century. Scientists soon began to realize that the great auk was disappearing and it became the beneficiary of many early environmental laws, but this proved ineffectual.
Its growing rarity increased interest from European museums and private collectors in obtaining skins and eggs of the bird. On 3 June 1844, the last two confirmed specimens were killed on Eldey, off the coast of Iceland, ending the last known breeding attempt. Later reports of roaming individuals being seen or caught are unconfirmed. A record of one great auk in 1852 is considered by some to be the last sighting of a member of the species. The great auk is mentioned in several novels, and the scientific journal of the American Ornithological Society was named The Auk (now Ornithology) in honour of the bird until 2021.
- "Great Auk" | 2021-11-13 | 43 Upvotes 27 Comments
Casuarius is a genus of birds in the order Casuariiformes, whose members are the cassowaries (Tok Pisin: muruk, Indonesian: kasuari). It is classified as a ratite (flightless bird without a keel on its sternum bone) and is native to the tropical forests of New Guinea (Papua New Guinea and East Indonesia), Aru Islands (Maluku), and northeastern Australia.
Three species are extant: The most common, the southern cassowary, is the third-tallest and second-heaviest living bird, smaller only than the ostrich and emu. The other two species are represented by the northern cassowary and the dwarf cassowary; the northern cassowary is the most recently discovered and the most threatened. A fourth but extinct species is represented by the pygmy cassowary.
Cassowaries feed mainly on fruit, although all species are truly omnivorous and take a range of other plant foods, including shoots and grass seeds, in addition to fungi, invertebrates, and small vertebrates. Cassowaries are very wary of humans, but if provoked, they are capable of inflicting serious, even fatal, injuries to both dogs and people. The cassowary has often been labeled "the world's most dangerous bird".
- "Cassowary" | 2022-09-20 | 17 Upvotes 13 Comments