There are about 10,000 living species of bird, they range in size from the 2 inch hummingbird to the 9ft Ostrich. They have all evolved from dinosaurs.
If we look at the modern birds, we find they have a range of common features, feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. All birds have forelimbs modified as wings. Most but not all can fly. Birds also have unique digestive and respiratory systems that are highly adapted for flight.
Generally they are underrated by people. Some birds, especially corvids and parrots, are among the most intelligent animal species; a number of bird species have been observed manufacturing and using tools, and many social species exhibit cultural transmission of knowledge across generations. If you observe them you will see they are often working in pairs or groups, and they can identify a human that is a risk to them from a friendly one. Many migrate huge distances, flying for example to Africa and back, and return to the same nesting location as the previous year. They are able to find their mate or young in large moving colonies, and many mate for life. They have a number of means of communication, both widely within groups of different species, and individually to their mates, or those who are encroaching on their territory.
They can be trained, used in performances, carry messages, to hunt or to identify approaching enemy risks.
Many occupy a world full of risk, predators on the ground, but often their main concern is other birds that are predators taking them from the air. Those that are the top predators are often persecuted by man, who feel they are a threat to game birds or other commercial interests, and although not supposed to, manage to poison and in other ways destroy them.
Since 1800 about 130 species have become extinct, and currently around 1,200 species are threatened by human activity.
Birds of Britain
Although there are 10,000 species in the world, the British list, that includes residents, annual visitors and occasional visitors numbers around 579, two of which are now extinct. The number of birds listed relating to the UK varies, from one online system to another and one book to another. The RSPB on its website lists 259 species, and in its garden bird identifier says it has 117, but has 91. However this does not include many that you might get in a farmhouse garden, or a garden near a lake, while some of those listed are unlikely to be encountered. Your geographic location within the UK would also have an affect on the birds that you see, the Welsh list has 436 species, take out the rarities and you have around 230 species, of these 150 bred annually in Wales.
Britain's smallest bird is the Goldcrest and its largest the Mute Swan. The oldest recorded wild bird was a Manx Shearwater that lived for 52 years, and is thought to have flown around 5 million miles each year on its annual migration with additional regular 600 mile feeding trips in between.
Britain's National bird, voted both in 1960 and again in 2015 by the British Public is The Robin. It is popularised and associated with Christmas in the UK appearing on many a Christmas card and decoration. There are a number of sports teams which are called 'The Robins' including Swindon Town football club in Wiltshire.
Birds break into two halves Passerines, and non Passerines, over half are Passerines, which means perching bird. There is however nothing that you can look at and say one is in one half or the other, its just where they are thought to have evolved from similar ancestors.
Below this beak we have a range of families, and looking through the options many are obvious, but many others are not. Ultimately the only way is to explore the groupings and see what is in each. The fact that a young blackbird looks like a thrush is a tip to where its hiding, but perhaps you may not realise some that are a part of the thrush family. The fact that jays and magpies are related to crows, ravens and rooks probably wont come as a shock. Ultimately having looked through the lists a few times the few discrepancies stand out and are easy to remember.
Equipment suitable for wildlife photography