Question: At Honolulu Airport recently, I noticed a bird cage on the ground behind a bench in the koi garden area. The cage, which was chained to a tree, was about 2 feet by 3 feet and maybe a foot tall. There were two Java finches trapped in it frantically trying to free themselves.

Several other Java finches kept flying to the cage, in what looked like an effort to free the trapped birds. This continued from about 4 p.m. until I had to leave at 7 p.m. This was very disturbing to me.

The man at the information desk, security personnel, maintenance personnel and airport workers - at least 15 people - knew nothing about the birds or seemed to care. I sat on that bench until it became dark, and no one came for the birds. They might have been there all night with no shelter whatsoever.

There was a dirty bowl of water and an almost empty bowl of birdseed in the cage. It was heartbreaking to hear their pitiful cries for help. Can someone explain why there was a cage in that garden trapping birds, and why nobody seemed concerned about their inhumane treatment?

Answer: The birds you saw, Java sparrows, were being trapped for safety reasons under a program required at all state airports by the Federal Aviation Administration.

The U.S. Department of Agriculture's Animal and Plant Health Inspection Service's Wildlife Services is under contract to the state to capture the birds, said Tammy Mori, spokeswoman for the state Department of Transportation.

The program aims to remove birds from airport areas because bird and other “;wildlife strikes”; can bring down aircraft in flight and injure people, she said.

Wildlife strikes, the vast majority involving birds, were reported 68 times at Honolulu Airport in 2007. Five of those strikes resulted in damaged aircraft.

The bird capture program is “;recognized nationwide as humane,”; Mori said. However, she did acknowledge that most of the captured birds are euthanized.

The birds used to be relocated and released, but that didn't work because the birds would too often return to the airport, she said.

Threatened or endangered birds are still being relocated and released, or taken to the Hawaiian Humane Society if they are in need of medical care.

Otherwise, “;common”; birds, such as Java sparrows, are euthanized according to standards set by the American Veterinary Medical Association.

Mori said another reason captured Java sparrows are euthanized is because they are known carriers of the West Nile Virus.

In addition to Java sparrows, other birds trapped at the Honolulu Airport garden areas include spotted doves and zebra doves, and occasionally, red crested cardinals.

At Honolulu Airport, there are five cages set out to trap the birds - two in the garden areas and three on the airfield. The cages are said to be checked twice a day, about 10 a.m. and 4 p.m., seven days a week.

We asked if small birds, such as sparrows, are involved in very many aircraft strikes and were told that sparrows in general, including house sparrows and Java sparrows, were involved in 10 strikes at Honolulu Airport between January 1990 and June 2008.

Although small, they often gather in flocks on the airfield, sometimes numbering more than 10, Mori said.

They can cause damage if multiple birds are hit in one incident. But one bird as small as a Java sparrow can cause costly damage to the fan blades of a turbine jet engine if it is sucked into the engine at high velocity.

Indirect damage costs to a carrier can include delays in flights because of a grounded aircraft, unsatisfied customers taking business elsewhere, costs to accommodate customers with hotels or other airlines if the carrier has no other aircraft available, etc., Mori said.

“;Most importantly, bird strikes with aircraft can lead to human injuries or worse,”; she said.

According to Bird Strike Committee USA (http://www.birdstrike.org/birds.htm), more than 195 people have been killed worldwide as a result of bird and other wildlife strikes since 1988. It also says they cause more than $600 million in damage to U.S. civil and military aircraft annually.

Pilots are required to report strikes when they occur, but the reality is that “;a considerable”; number go unreported if no damage is sustained to aircraft, Mori said.

Between January 1990 and June 2008, a total of 1,861 birds - plus four cats and one dog - were recorded as wildlife strikes at Hawaii airports, according to the FAA's National Wildlife Strike Database (see wildlife.pr.erau.edu/ database/select_iv.php).

The bird capture program involves a cooperative service agreement in which the federal government pays for the program, then is reimbursed by the state.

On Oahu, the program covers the Dillingham and Kalaeloa airfields, as well as Honolulu Airport, and costs $549,000 annually, Mori said. Statewide, the total cost is $1.5 million annually.

Meanwhile, airport-goers and employees are asked not to feed birds at the airports.