"A recent field survey shows that the gorges of Seshe and Maolin Ecological Park in the Maolin National Scenic Area (MNSA) - the traditional winter habitat of the special migrating butterfly species - have remained mostly unscathed, " Wu Mao-sheng, director of MNSA Administration in southern Taiwan's Kaohsiung County, said Thursday.

Usually the colorful creatures begin arriving in large numbers in Maolin's valleys in November, but this year, the first flocks arrived in early October, Wu said.

"The number of wintering purple crow butterflies is expected to be impressive this year, judging from the fact that the number of those arriving in October far surpassed the figure recorded for the same period of last year," Wu said.

About 400,000 purple butterflies were documented in the Maolin valleys last year, according to volunteers from the Taiwan Purple Crow Butterfly Ecological Preservation Association.

With the drop in temperature in northern Taiwan in recent days, volunteers said they expect more butterflies will come to Maolin for wintering this year and that the number may match the previous high of 1 million.

"At most, more than 100 butterflies will flutter over one's head in five minutes, " said one volunteer from the association which collaborated with the MNSA office in conducting an in-depth location survey in October.

As most butterfly flocks rest within valleys of higher altitude, tourists can only see scattered butterflies within river valleys during sunny mornings, the volunteer said.

In recent years, the MNSA Administration has regularly organized butterfly watching activities to allow more wildlife enthusiasts to admire the creature close up through guided tours.

Wu said a biennial butterfly watching program is scheduled to be inaugurated on Dec. 12 and runs until March 6, 2010. Mountainous townships in the region, including Maolin, Liuguei, Taoyuan, Sandimen, Majia and Wutai, were all severely devastated by Morakot-triggered flooding and landslides.

After three months of closure to tourist visits, major pathways in the region have been repaired and paved with asphalt, Wu said.

"While large coaches will still be barred from entering due to safety concern, medium-size passenger buses, SUVs and compact cars can cruise the area safely," Wu said.

As a prelude to the biennial butterfly watching festival, Wu said his office will join forces with the Liuguei township office in organizing a drumming event at the township's Baolai Junior High School this weekend to console the many typhoon survivors in the region.

The renowned U Theatre will head a group of hearing-impaired students in performing its signature drum piece Mandala Dedication, which was presented in the opening ceremony for the 2009 Summer Deaflympics held in Taipei in September.

The program will be named "Drum Wish" as organizers hope that the beat and rhythm of drumming will encourage typhoon-affected people to regain faith and rebuild their lives and careers.

In late October or early November each year, instinct draws purple crow butterflies to take refuge in low-lying valleys on the two sides of the southern foothills of Taiwan's Central Mountain Range, most notably Maolin in Kaohsiung County and Dawu in Taitung County, where they winter until March.

At the onset of spring, the butterflies begin a 400-km migration back to their northern habitats, following a variety of routes from Maolin and Dawu until they reach the hillside village of Pingding in Yunlin County, where they converge in the thousands or even millions before crossing the Chingshuei River in south-central Taiwan.

The butterflies then fly to different destinations in central, northern and northeastern Taiwan, including Baguashan in Changhua County and Jhunan in Miaoli County, where they fulfill their most important mission -- to mate and lay their eggs.

This butterfly migrating spectacle is almost unique to Taiwan.

The only other place where this can be seen is in Mexico, where the monarch butterfly is the only other butterfly species to migrate like birds and winter in a particular valley, according to local conservation activists.

(By Chen Shun-hsieh and Sofia Wu)