The attractive appearance and the couple's dedication to mating, during most part of the year, are some of the reasons this is considered a special bird.

CaulkerThe delicate and exotic beauty of the Caulker has helped make it one of the most bred birds in the world. The red tones of the beak, in a peculiar conic shape, appear also in the rims around each eyes. In fact, its beak is transluscent, and the reddish color comes from the blood that circulates in it. The black head, with a white spot, crowns the gray body, the original color, which can also appear in lighter or darker shades. It is also found in mutations of several colors.

The Caulker comes from Indonesian islands such as Java, Sumatra and Borneo; it flies in groups, and is considered a plague near rice crops. Its scientific name, Padda (Lonchura) oryzivora, means "rice eater". It's also known as Java or Pada Sparrow. The Caulker's popular name comes from an interesting comparison. The way ancient sailors in charge of calking ships worked is similar to the way this bird builds its nest, as if it were a hollow ball, whose walls the Caulker "calks" so well the light cannot infiltrate it; there is only a small opening for it to go in and out.

Indonesia, and its islands, belonged to Holland since the 17th century, and the sailors from this country spread the Caulker around the world. The route of this spreading began in Zanzibar, Mauritius Islands, Saint Helena and went on to India, Malasya and parts of China. They later arrived in Europe, where its first successful amateur breeding dates back to 1890, in Switzerland.

The Caulker has been in Brazil for more than 40 years. It lives and grows well here, because it is a bird of hot climates. It was brought here both by Brazilian breeders, who traveled to Europe to get it, and eastern sailors, who brought these birds with their luggage.


Resistant, the Caulker lives well in outdoor aviaries, where it can be bred in colonies or along other species, such as the Australian Pakakeets and Mandarin Diamonds. The breeders prefer having them in cages though, only in pairs, where they grow sweeter, let people get close and breed normally. "In the aviary, the bird usually gets scared with the aproaching of people, and the beak suffers from the beating on the bars," comments Hermelino Bosso, from Criadouro São Vicente, in Mauá, São Paulo. "Besides, in an aviary, it may get into disputes for nests with other couples, and this can be a stressing situation for them."

The male is an excellent father. It usually helps his companion in all possible phases of the breeding. In March, along with the female, he plaits the straw and carefully makes a nest. They are so careful not a single leaf is left there, however small. They then mate. As soon as the female lays the eggs, they both take turns hatching, and later, they feed the babies. This whole process lasts around two months. Soon after that, the cicle begins again, and then again, and again, until the end of October. A new phase starts then: the physical recuperation of the organism, weary because of the breeding period. This lasts until March, during which time they moult (two months at the most). When moultin is over, they restart breeding.


The Caulker gets easily stressed in trips, and may even die, so it demands special care during transportation. Hermelino, for instance, normally takes his birds to compete in expositions. To protect them, he puts them in transportation boxes. But they get scared even in this situation, maintaining their eyes closed, not opening them until the trip is over. To make them feel more at ease, Hermelino stops every two hours, gets them out of the boxes, puts them in their respective cages, for a 30 minute rest. He also puts two drops of water in their beak, to ease the thirst caused by stress.

The breeders recommend never to transport the Caulker during the moulting. In this period, they are less resistant, increasing chances of stress being fatal.


The gray body of the original Caulker can appear in darker or lighter tones. The breeders prefer the dark gray. There are also other mutations:


Size: Small, may reach up to 15cm.
Housing: Place must be protected from winds and rain, with lots of light. Aviary: up to 5 couples (1,5 m long x 1 x 1, with canvas only in the front part, completely covered with clay tiles. Cage: GR3 with 70 cm x 40 (width) x 30 (height).
Transportation box: Made of wood, 40 cm x 25 x 10, only one side in canvas: up to 10 birds.
Feeding: Granivorous. Daily give them generous portions of commercialized granivorous food, or a mixture of non-washed seeds (for 5 couples, monthly amount: 5kg millet, 2kg of birdseed, 1kg of oats). To complement this diet, give them chopped apples, kale, chicory, escarole and insects, twice or three times a week. Hang 1/4 of a raw green corn in the cage, 2 or 3 times a week. Water: must be available at all times.
Sexual identification: The adult male sings more, its beak occupies a larger area of the face, and the red rim around eyes has a more intense color.
Nest: A wooden cube, 20cm x 20 x 20, with a lid, place outside the cage, and with round opening facing inside of cage. If box is any smaller, this can harm female bearing. Em aviary, place one extra nest. In cage, put the nest along with the couple, after 10 months of age.
Breeding: Beginning of March. During 4 days, place some straw for each nest. While straw is available, the couple builds the nest - a hollow ball which occupies all the space of the wooden cube. After nest is ready, owner can cut the top part of the ball with a pair of scissors, for inspection when opening lid. Never clean the nest. The female gets nervous, and this hinders breeding. A month and a half later, female starts laying eggs; 4 to 6 eggs (this takes 4 days). After the last one is laid, she starts hatching, takin turns with male. After 15 to 16 days, ovos hatch. Babies should be separated from parents when they are 35 days old. A nova bearing starts 3 days later. From March to October, there are 4 or 5 posturas. The couple breeds around 20 babies per season.
Hygiene: The Caulker loves to bathe. During breeding time, in hot days, daily place a bowl or saucer with water for bathing. During moultin (November to February), do this only once a week.
Health: There are no specific diseases. Good hygiene and feeding are enough. If beak is almost white, it is a sign of anemia.
Moulting: If it lasts more than 2 months, this means trouble.

We would like to thank the people interviewed, and also Paulo Flecha, from the Sociedade Ornitológica Bandeirante, and Veterinarian Stella Maris Benez, from Clínica Proave, in São José dos Campos, state of São Paulo.
Research: Claudia Picazzio Text editor: Marcos Pennacchi

Picture: Fernando Torres Andrade
Owner: Hermelino Bosso

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