Such sleep-induced side effects while on the medications have been around for years, but the incidence is rising because of an explosion in the drugs' use, specialists said.

About 30 million people in the United States take sleep medications, according to the American Academy of Sleep Medicine. By some counts that is a 50 percent jump since the beginning of the decade.

Some of the most serious side effects are short-term memory loss, and accidents involving patients who drive the next day while still feeling drugged.

"Patients who may have engaged in this unusual behavior at night -- it's relatively rare and bizarre," said Donna Arand, president of the American Insomnia Association.

"The daytime sleepiness -- that drugged feeling that people may have -- is probably the most worrisome because of the (vehicular) accidents that can occur."

Other insomnia medications are Lunesta from Sepracor Inc. and Sonata made by King Pharmaceuticals Inc.. In the $2 billion U.S. market for the drugs, market leader Ambien boasts 12 billion nights of patient use.

Increased use of the drugs is spurred in part by heavy advertising and patients may be using the drugs for longer periods than they are intended, experts said.

Consumer group Public Citizen warned that Ambien should only be used on a limited basis because it causes temporary amnesia, according to pharmacist Larry Sasich.

Because the Food and Drug Administration's reporting system is voluntary and anecdotal, "we don't know how big a problem it is ... we have no way to accurately to assess the prevalence," said Sasich a consultant for Public Citizen.

Sanofi-Aventis said sleepwalking is a rare side effect listed on Ambien's label and that it reports all events to the FDA. Still, it had no statistics about the prevalence of sleepwalking.

Ken Sassower, a staff neurologist at Massachusetts General Hospital in Boston said a colleague who had taken one of the sleep drugs could not recall advising residents on rounds the next morning.

"The memory issue may be an infrequent side effect, but when it occurs it can be pretty significant ... certainly that needs to be looked at in a more rigorous way," he said.

Doctors recommended against abruptly stopping the drugs, which can cause withdrawal symptoms including seizures.

"The risk was always there; we are seeing it more now because so many more people are using the drugs," said Merrill Mitler, program director at the sleep disorder unit at the National Institutes of Health.

With so many wondering what happened, the Air National Guard is continuing its investigation.

That leaves others to speculate about meteors and to do comparisons with a similar unexplained phenomenon in Florida last year and in Maine just last month.

Others speculate it is a secret government plane, code-named Aurora, which supposedly flies out of Area 51 in Nevada.

For years, unusually intense sonic booms rocked Los Angeles, with many believing it was Aurora passing by at four times the speed of sound.

Those postings and printings are evidence of a growing public interest in the Mayan Long Count calendar, which had fallen out of use by the Mayans of Guatemala, Mexico and Belize, long before the Spanish conquerors had arrived.

The 2012 date is the last day of the current "b'aktun" cycle, or period of 144,000 days, and the final day of an even longer period consisting of 13 such cycles. No one knows why the calendar is arranged with an end date, Sitler said. But the Mayans were known for their accurate knowledge of astronomy.

"It's a weird concept to many because the calendar seems to have a preordained ending date," said Jeremy Puma, a Seattle resident and St. Augustine native who writes Fantastic Planet, a "gnostic" blog. He noted in an e-mail interview that the Mayans used the calendar for planting crops and other purposes, but the New Age movement "seems to have glommed onto the calendar's more mythological aspects."

First and foremost, Sitler and Puma agree, is New Age author Jose Arguelles, most famed for his declaration of a "Harmonic Convergence" in August 1987. The Harmonic Convergence, Arguelles said, was the "exponential acceleration of the wave harmonic of history as it phases into a moment of unprecedented synchronization," and "a shift point into the last 25 years of the galactic beam."

Sitler says Arguelles' approach is Mayan culture with "creative abandon," and when challenged, will note that his version of a 260-day Mayan ritual calendar, which differs significantly from the actual calendar used by some Maya even today, is a version of the "Galactic Maya," rather than the indigenous Maya.

"Arguelles is merely the best-known teacher in an ever-expanding international group that includes dozens of highly inventive and often eccentric individuals reaching out to the New Age public with their ideas concerning 2012," Sitler said. He notes the existence of a Web site that features a running clock until Dec. 21, 2012, with links to another selling T-shirts bearing the 2012 date and featuring several pop-up ads.

Despite the blatant commercialism, there remains a lot of interest in the subject, said Jeff Dorian, director of the MetaScience Research Forum, a local group that meets monthly at the Edgewater Public Library. Dorian said he has long wanted to land an expert in the Mayan calendar to speak to his group.

"There is a percentage of people who believe the end of the Mayan calendar will be the end of everything," Dorian said. "There's about as many interpretations of the Mayan calendar as there are experts."

Inside an Ormond Beach New Age shop, the Crystal Connection, a thumping of drums, soft whistle of a flute and screech of an unidentifiable rainforest avian greets visitors. Books line the shelves, carrying titles such as, "The Fourth Dimension," "The Book of Thoth," and "Waking the Tiger: Healing Trauma." Also available: pyramids, amethysts from Uruguay, angels and fairies (spelled "faeries", presumably to seem more Gaelic).

Roger Hollander, owner of the shop, said he doesn't believe 2012 will bring the end of the world. But, he adds: "There are many people that believe this. Some believe this strongly."

Hollander, who also owns similar shops in Indian Rocks Beach and St. Augustine, believes a change could be coming in 2012.

"The world will have a better, a deeper sense of consciousness. By then, (people) should be worn out doing it how they're doing it now. We'll either be here or we won't; we'll just have to experience it."

Sitler predicts the Mayans' culture could lend 2012 "an attractive power that may eventually even outstrip" Y2K, the hype surrounding the year 2000.

Dr Tim Guilford of Oxford University thinks they do it by using visual landmarks. Guilford, himself a champion paraglider, says: "When you're flying you realise that what is normally a three dimensional landscape becomes very two dimensional, almost map-like.I think that's the way birds see the world."

He and his colleagues have attached GPS devices to pigeons that log their flight. Using Ordnance Survey maps it appears that pigeons do seem to follow major routes, like roads, back home. When they've been released in an unfamiliar location, the pigeons circle, before flying to an obvious landmark like a church and picking up their normal route again.

Even though Guilford's findings back up this suggestion, more than 30 years ago it was shown that pigeons wearing opaque contact lenses could still find their way home. Nor does it explain how birds like the Arctic tern can circumnavigate the globe without ever having been to the place they're headed for.

Professor Wolfgang and Dr Roswitha Wiltschko of Frankfurt University believe it's down to magnetism. They claim that pigeons have a compass in their eye and a magnetometer in their beak to measure the intensity of the earth's magnetic field, and thus whether they are north or south of home. Roswitha says: "You know when you are standing upright and I think it's something similar to that."

The pair could be on to something. In Science, Dr Kenneth Lohmann, from the University of North Carolina, published evidence that suggested baby turtles navigate through the Sargasso Sea using a magnetic map. He exposed loggerhead turtles to a magnetic field generated by an electric coil that mimicked the earth's magnetic field at three key locations along their route. When the turtles were exposed to a field like the one that occurs near Portugal, the turtles paddled south, which is what they would have done had they really been swimming in the area.

A third theory comes from Dr Anna Gagliardo, who believes that pigeons navigate by smell. Gagliardo, from the University of Pisa, claims the birds follow scents blown in on the winds. Harry Marshall agrees. "It's not about following a scent trail," he says. "Each landscape has its own olfactory signature. The birds then remember where these lie in relation to each other, like a patchwork of odours."

Gagliardo has some convincing evidence to back up her claims. She raised two groups of pigeons in sheds made of chicken wire, one of which had glass put round it so that any wind blowing in had to come in through the top. The pigeons in the open roost experienced breezes with distinct regional scents attached; those encased in glass had wind and smells, but did not know which scent had come from which direction. Gagliardo then released the pigeons over a lake so that they would not have any landmarks to use as guides. The pigeons who had been in the glass-enclosed shed were not able to find their way home, but those who had been in the other shed were able to.

But one man disagrees with all these theories. Dr Rupert Sheldrake believes that animals use what he calls "morphic resonance". He thinks that there is a memory in nature, and that objects resonate with it, so that pigeons will return to their loft as if attached by an invisible elastic band that stretches through the cosmos. In a cunning experiment, the Paranormal Pigeon team set out to test his hypothesis. With the help of Ragsy, a pigeon fancier, pigeons were raised in a shed in Sharpness Docks in Gloucestershire. The loft was floated a few miles up and down the canal, showing the pigeons that their home could move - not something that they would ever have come across. Then the loft, minus its inhabitants, was towed out to sea and the pigeons were released from Sharpness. Ragsy waited by the shed, growing increasingly seasick. Eventually the floating shed was towed back. The pigeons were sitting waiting, 55 hours later, when their home reappeared. The cosmic elastic band seemed to have snapped.

David Coleman a resident of West said, "We thought it was kind of weird, he just fell out of the sky and there was a bunch of them flying over."

Even on Monday, we found the remains of birds throughout the city, and that made some people think the worst.

"You think about the bird flu that's been mentioned recently that was my first thought, that this bird was sick, and we were kind of scared about that," Coleman said.

The good news is it's not the bird flu, according to the Texas Department of Wildlife. But officials say as a precaution, the dead birds should not be handled.

The west police department is also looking into the deaths. And Wildlife experts admit they still don't know what killed the birds, but they're running tests on some of the carcasses they collected. And in the meantime, they warn this could happen again.

The state department of wildlife tells us it's actually common to see bird deaths this time of year. Most of the dead birds in this case were discovered in a four square block area of west near downtown.

The pair watched it for a couple of minutes, rotating in the distance and heading towards Wandsworth Town. Then, as soon as it had appeared it vanished.

Michelle said if it was a piece of rubbish it would have caused severe damage when it came down, because of its size and density.

"I can't explain it and therefore I'm calling it a UFO. It took my breath away. It did feel weird.

"The more I looked at it I realised there was something not quite right. It wasn't moving like anything I've ever seen before," she said.

A spokesman for the Ministry of Defence (MoD) said it had not been notified of any sighting of the pyramid.

"The MoD does not have any expertise or role in respect of UFO/flying saucer' matters or to the question of the existence or otherwise of extraterrestrial lifeforms, about which it remains totally open-minded."

He said it examined the reports of UFO sightings it received solely to establish whether what was seen might have some defence significance, namely whether there was any evidence the UK's airspace might have been compromised by hostile or unauthorised air activity.

Michelle and Peter said there has been a lot of activity in the skies over Putney recently.

Michelle said they had seen several Chinook helicopters over the past week and believes something must be happening.

Chinooks are used to transport troops, artillery, supplies and equipment, but also used for operations such as medical evacuation, disaster relief and search and rescue.

When travelling to Putney, our reporter saw what looked to be three Apache helicopters travelling east.

A spokesman for the MoD said the helicopters were probably part of general aviation traffic over London and there was no specific activity or event they were involved in. He added such movements were "not unusual".