Birds are a group of warm-blooded vertebrates constituting the class Aves, characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m (9 ft 2 in) common ostrich. There are about ten thousand living species, more than half of which are passerine, or "perching" birds.
Birdwatching, or birding, is the observing of birds, either as a recreational activity or as a form of citizen science. A birdwatcher may observe by using their naked eye, by using a visual enhancement device like binoculars or a telescope, by listening for bird sounds, or by watching public webcams.
Most birdwatchers pursue this activity for recreational or social reasons, unlike ornithologists, who engage in the study of birds using formal scientific methods.
There are about 10,000 species of bird and only a small number of people have seen more than 7,000. Many birdwatchers have spent their entire lives trying to see all the bird species of the world. The first person who started this is said to be Stuart Keith.
Birders have been known to go to great lengths and some have lost their lives in the process. Phoebe Snetsinger spent her family inheritance travelling to various parts of the world while suffering from a malignant melanoma, surviving an attack and rape in New Guinea before dying in a road accident in Madagascar. She saw as many as 8,400 species. The birdwatcher David Hunt who was leading a bird tour in Corbett National Park was killed by a tiger in February 1985. In 1971, Ted Parker (who later died an air crash in Ecuador) travelled around North America and saw 626 species. This record was beaten by Kenn Kaufman in 1973 who travelled 69,000 miles and saw 671 species and spent less than a thousand dollars.
In 2012, Tom Gullick, an Englishman who lives in Spain, became the first birdwatcher to log over 9,000 species. In 2008, two British birders, Alan Davies and Ruth Miller, gave up their jobs, sold their home and put everything they owned into a year-long global birdwatching adventure about which they a wrote a book called The Biggest Twitch. They logged their 4,341st species on 31 December 2008, in Ecuador. Noah Strycker recorded 6,042 species during 2015, overtaking Davies and Miller. In 2016, Arjan Dwarshuis became the world-record holder for most species seen during the span of one year, logging 6,852 bird species in 40 countries.
Birdwatching literature, field guides and television programs have been popularized by birders such as Pete Dunne and Bill Oddie.
