The Dilute budgerigar mutation is one of approximately 30 mutations affecting the colour of budgerigars. It is one of the constituent mutations of several recognised varieties: the Light, Dark, Olive, Grey and Suffused Yellows and the Grey and Suffused Whites. Appearance The Dilute mutation changes the body colour of the wild-type Light Green to yellow, with a variable amount of light green suffusion. The suffusion is deepest on the rump and around the vent. The spots and markings on the wing, head and neck, which are black in the wild-type, are pale grey. The cheek patches are pale lavender and the long tail feathers are pale bluey-grey. The eyes remain normal, with white irises when adult. There is considerable variation in the intensity of the green suffusion, but the best exhibition birds of the 1930s showed very little and also had very faint wing markings. These are the Dilute Light Greens, usually known as Light Yellows. The green suffusion becomes progressively darker when single and double factors of the Dark mutation are present. These are the Dilute Dark Greens and Dilute Olives, usually known as Dark and Olive Yellows. When the suffusion is particularly heavy the bird is known as a Suffused Yellow. In the blue series the absence of the yellow pigment turns the body colour to white, although this is usually suffused with blue, often quite heavily. When the suffusion is light, Dilute Skyblues are known as Whites; when it is heavy they are known as Suffused Whites. Dilute Cobalts and Mauves are usually known as Suffused Whites. Historical notes Budgerigars were first introduced into Europe by the ornithologist and bird artist, John Gould, in 1840, when he imported to England a pair which had been bred by his brother-in-law, Charles Coxon. They grew steadily in popularity. For the first thirty years of their domestication only the wild-type Light Green budgerigar was known, but in 1872 birds with greenish-yellow bodies and very pale wing markings were reported from Belgium (in both Brussels and Antwerp) and Germany (in both Kassel and Berlin). This, now known as the Dilute mutation, was the first mutation observed in the domesticated budgerigar. Joseph Abrahams obtained some of these new yellow birds from Belgium and bred the first Yellow, as it was called, in Great Britain in 1884. These strains, in both Britain and Europe, laid the foundations for the very popular exhibition Light