The budgerigar (/ˈbʌdʒərɪɡɑːr, -əriː-/ BUJ-ər-ih-gar, -⁠ə-ree-;[3] Melopsittacus undulatus), also known as the common parakeet, shell parakeet or budgie  (/ˈbʌdʒi/ BUJ-ee),[3][4] is a small, long-tailed, seed-eating parrot. Naturally, the species is green and yellow with black, scalloped markings on the nape, back, and wings.[5] Budgies are bred in captivity with colouring of blues, whites, yellows, greys, and even with small crests.[5][6] Juveniles and chicks are monomorphic, while adults are told apart by their cere colouring, and their behaviour.