A live black hornbill chick was rescued from two men who had tried to smuggle it in a paper bag across the Causeway into Singapore.
In a joint statement on Wednesday, the Agri-Food and Veterinary Authority and the Immigration and Checkpoints Authority said that the two men were caught at Woodlands Checkpoint on May 12.
The black hornbill chick was hidden in a paper bag in the front compartment of a Malaysia-registered motorcycle.
Syed Muhammad Syed Hassan, 29, and Mohammed Ali, 35, were fined $4,000 each for illegally importing the chick, a protected species under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (Cites).
The baby bird is now in the care of Wildlife Reserves Singapore.
Importing animals and birds without a licence is an offence under the Animals and Birds Act, punishable upon conviction by a jail term of up to 12 months, or a fine of up to $10,000, or both.
Importing an animal of a species protected under Cites is also illegal, and offenders can be fined up to $50,000 per animal (not exceeding a total of $500,000) or jailed for two years, or both.
In separate court cases on Wednesday, two men were fined for wildlife-related offences.
Muhammad Effendi Roslan, 27, was fined $6,000 for the possession of an Indian star tortoise, one scorpion, one red-bellied short-necked turtle and two corn snakes.
Lawrence Wee Soon Chye, 52, was fined $5,000 for illegally importing five leopard geckos.
In the statement, the authorities said that Singapore's borders are the first line of defence in safeguarding the nation's safety and security.
"Animals that are smuggled into Singapore are of unknown health status and may introduce exotic diseases, such as bird flu, into the country," the authorities said.