Badminton fanatic Dan Chien began noticing a change in his shuttlecocks a few months ago.
The feathers seemed thinner and his shuttlecocks were falling apart at an alarming rate.
"Everybody complains now, 'What's wrong with the shuttle?' " he said one morning as he anticipated an evening full of hard-hitting matches at the San Gabriel Valley Badminton Club in El Monte.
Chien knows why. After a practice session, he groused: "It was goose feather, but now it feels almost like duck."
Bird flu has killed 134 people around the world, sickened hundreds more and forced the culling of millions of poultry from Vietnam to Nigeria.
Now it is smashing the world of badminton.
The heart of the game is the shuttlecock, the best of which are made of goose feathers plucked in northern China.
Those geese have been slaughtered by the millions to contain the virus, causing a feather shortage that has unnerved the badminton world.
"I believe the problem is potentially considerable," said Torsten Berg, the official bird flu spokesman for the International Badminton Federation.
The shortage has been particularly felt in Southern California, home to some of the country's best players, coaches and clubs.
Prices on premium shuttlecocks, which cost up to $25 for a tube of a dozen, have risen 25% in the last few months.
Manufacturers are competing for the limited feathers, and players are scrambling to buy the best birdies in bulk, further restricting supply.
Die-hard players are bracing for the worst.
As the virus has spread from Asia to Africa and beyond, scientists have grown increasingly concerned that it could mutate into a form easily transmitted among humans, leading to a pandemic that could kill millions.
Ahmad Bakar, 54, managing director of Pacific Sports Private Ltd., which sells shuttlecocks under the Ashaway brand, acknowledged that a pandemic would be a disaster.
But he can't help expressing a more personal concern.
"If bird flu becomes pandemic," he sighed, "shuttlecock prices could become twofold or threefold higher."
The premium shuttlecocks prized by Chien and other serious players have little in common with the cheap plastic variety strewn across American lawns. The birdies, as some call them, must be tough enough to endure smashes that can send them whizzing at up to 150 mph and shaped just right so their arcing flight is predictable and consistent.
Most of the best tournament-level birdies come from China. Each is made of 16 hand-selected feathers punched into a cork base and held together with string and glue. Sometimes, one goose will yield just two of these precious feathers.
At the factory of the Postsky Racquet and Shuttlecock Co. in Guangzhou, the feathers are sifted, trimmed from 8 inches down to 4 inches, sorted by curvature and inserted into cork imported from Portugal.
Only the thickest and most regular feathers are used for high-grade shuttlecocks. Lower-grade shuttlecocks use thinner, slightly irregular goose feathers or duck feathers, which are less durable.
"It's like an art," said William Chan, the U.S. distributor of premium Hi-Qua birdies, which are made at the Postsky factory.
Chan, who runs his shuttlecock business out of his Rowland Heights home, said the feather supply began to tighten about a year ago, pushing up wholesale prices from about 3 cents each to 4 cents.
That may not sound like much, but it adds up. The Postsky factory, run by Chan's brother Chester, uses about 4.8 million feathers a month.
"We haven't raised our prices for over 10 years, but now we have to," said Chan, 51.
After a rash of broken birdies, out-of-control kill shots and careening flicks, players now suspect that shuttlecock makers have begun substituting lower-quality feathers in their premium tubes.
Chan conceded there was some truth to the suspicion.
"Maybe in the old days, they only used the best kinds of feathers for the top grades," he said. "But right now, feathers on the borderline may get put in because of the cost."
Bakar, of Pacific Sports, said all of his company's top shuttlecocks had maintained their quality, but since the emergence of bird flu, "all brands have to have a mixture in grade."
Manufacturers "cannot get enough good feathers, and even if they could, if they were to put the good feathers in the shuttlecock like before, it would not be a 25% increase, but 50%," he said.
Players say they can easily tell the difference.
Chien, 35, a West Los Angeles cellphone accessories consultant who practices daily at the San Gabriel Valley club, said a doubles match used to destroy eight to 10 shuttlecocks. Now it's twice that number.
"For advanced players, it makes a very significant difference," he said. "They say football is a game of inches. Badminton is too."
Chien said he recently prayed aloud for salvation from the scourge of bird flu.
He prayed not only for sick people, but also for all geese.
His mother laughed at him.
Players have been trying everything to extend the life of their feather birdies, including steaming them or putting them in the refrigerator, which can plump up feathers and make them last longer.
Another solution has been to simply hold out on friends.
Badminton etiquette demands that all players on the court contribute at least one birdie during a game, explained Adam Poon, 32, a lanky Rosemead student and jewelry store clerk, between matches at the San Gabriel Valley club.
During a recent doubles match, three players pulled out their birdies, but one man said he had run out.
"They don't want to take out birds now," Poon grumbled. "They're getting kind of petty."
Shuttlecock makers have also begun to search for alternatives.
Bakar said his company began developing a nylon shuttlecock last year that he thought was as good as the best available feather shuttle on the market.
"I think in the past, nobody really paid attention to research in nylon shuttles because feathers were available and cheaper," he said.
The International Badminton Federation also has intensified its funding for synthetic shuttlecock research, though the results are lagging.
"Feathers are actually quite unique," said Berg, the group's vice president. "The birds have done a good job developing feathers."