Call ducks (miniature ducks) were bred in the 19th century in Great Britain from Dutch lines of decoy ducks. They were bred to be super small so that they could lure wild ducks into traps and be able to escape through a tiny trapdoor. Call ducks could attract lots of wild ducks because their "call" is so loud it can be heard extremely far away.
The American Poultry association currently recognizes only 9 varieties (colorations) of call ducks: Blue Bibbed, Blue Fawn, Buff, Butterscotch, Chocolate, Gray, Pastel, Snowy, and White, but many breeders have developed other colorations.
Unlike most other breeds of ducks, it is impossible to sex call ducklings when they are one day old because of their extremely small size. Once they reach five weeks old females are distinguished from males based on their call. Males make a soft quack whereas females make a piercing loud quack. Male ducks will develop curling sex feathers on their tails, and generally have much brighter colorations than females of the same variety.
Call ducks are 1/3 the size of a mallard duck, and are the smallest recognized breed of duck in the U.S. These ducks can live upwards of ten years in captivity. Show quality call ducks can cost upwards of $1,000, however, pet quality ones can be as low as $20. Call ducks don't have large feed expenses compared to other ducks but you can expect to pay $5-10 per bird per month, as well as $10 a month on bedding.
The best thing to feed call ducks is a feed made specifically made for ducks. This is often hard to find, though, so many people just use chicken feed. This can be costly because chicken feed doesn't have niacin in it which is an essential part of a call duck's diet, and lack of it could cause seizures. Niacin can be supplemented with brewer's yeast, black oil sunflower seeds, or spinach. Call ducks also need calcium, which can be provided to them with oyster shells. Calcium helps make their eggs stronger and prevents egg binding.
Call duck eggs are relative to their size, which makes them quite small. They are generally a light green color, but also come in white, blue, and light pink. Call duck eggs (and all duck eggs) have a very similar taste to chicken eggs, but they are even better to use for baking because they make foods fluffier and richer. Plus, duck eggs are much healthier than chicken eggs!
The general rule for the size of a duck coop is four square feet per bird, but since call ducks are smaller, it's okay to give them less than this. The outside wires on the coop should be no larger than 1/4" hardware cloth since this is the only way to ensure protection from predators. Chicken wire is too big and allows predators like weasels, fisher cats, and raccoons to access the birds inside.
All in all, call ducks make excellent and rewarding pets. They are generally very friendly and if raised correctly can be trained to walk on leashes and make great companions.