INDONESIAN police have found more than 24 cockatoos stuffed in plastic bottles by smugglers trying to get through customs at the Port of Tanjung Perak in Surabaya, Indonesia.

The yellow-crested cockatoos were cut free from their plastic prisons and given medical attention after the shocking discovery, reported The Daily Mail.

The birds can fetch about $1,300 each, and were to be smuggled out of Indonesia to be sold on the black market, the Daily Mail reported.

About 40 per cent of the birds die as they are smuggled illegally, due to the poor conditions they are smuggled in, according to the paper.

In 2007, the species of yellow-crested cockatoos was listed as critically endangered by the International Union for the Conservation of Nature and Natural Resources.

Its population is critically low. Studies say there may be less than 7,000 remaining.

In 2004, a wildlife watchdog told The Jakarta Post that bird smuggling was the second-largest crime in the country after drug trafficking in terms of the number of cases.

An executive of the Bogor-based Network Development Birdlife Indonesia, Mr Yusup Cahyadin, said the most popular birds are cockatoos and parrots, which are smuggled overseas from Tobelo Halmahera district, North Maluku.

"The birds are taken directly off the island by fishing boats from Singapore and the Philippines. The Eastern Naval Fleet has been unable to curb the crime, maybe because their surveillance area is too vast," he told The Jakarta Post at the time.

According to the Post, There are 14 types of protected cockatoos, including the great sulfur-crested cockatoo (Cacatua galleria) and sulfur-crested cockatoo (Cacatua sulphurea), white-colored goffin (Cacatua goffini) and salmon-crested cockatoo (Cacatua molucensis), all of which are indigenous to the islands of eastern Indonesia, including Maluku.

The red-and-blue lorry (Eos histrio), yellow-backed lorry (Lorius eclectus/roratus), black-capped lorry (Lorius lory) and black-lored parrot (Tanygnathus Sumatranus) are some parrot species that are protected.

The Convention on International Trade in Endangered Species of Wild Flora and Fauna stipulates that protected avian species can be traded only if they originated from breeding facilities, not directly from nature.

Under laws on conservation of biodiversity and ecosystem, traders and owners of protected animals face a jail term and a fine, but the laws have not been stringently enforced, and endangered bird and animal species can be seen on display openly at street-side markets in Indonesia's capital and other major cities.