honoluluadvertiser.com

Sponsored by:

Comment, blog & share photos

Log in | Become a member
The Honolulu Advertiser
Posted on: Saturday, June 8, 2002

Bat stages rare show on O'ahu

By Jan TenBruggencate
Advertiser Science Writer

When a bat flew over Theresa Menard's Pupukea home just after sunset, she knew it was something special.

Bat expert Theresa Menard spotted an endangered Hawaiian hoary bat flying after sunset near her Pupukea home. It's the first she has seen on O'ahu.

Gregory Yamamoto • The Honolulu Advertiser

That's because Menard is perhaps the state's top expert on the endangered Hawaiian hoary bat, and she knew it was the first confirmed sighting of the animal on O'ahu in a long time.

The bat appeared a half-hour after sunset on several occasions in the past week, and appeared to be feeding as it fluttered by.

"In my 12 years of living on this island, I'd never seen a bat here before this weekend," Menard said.

She has seen plenty of bats in certain areas of Kaua'i and the Big Island, but they are far less common on other islands.

Bats apparently were common on O'ahu two centuries ago. In Quentin Tomich's book "Mammals in Hawai'i," he writes of an 1816 expedition in the Pearl City area, where a cloud of bats appeared and one was shot.

There are no reports since then of bats being common or dense. Most reports of sightings have been by people who are not experts. It is easy to mistake certain large moths for bats, Menard said.

The best recent unconfirmed sighting was a couple of years ago by Army biologists in Makua Valley, she said.

Bat buff seeks stories

Bat expert Theresa Menard said she is interested in hearing of other sightings, through e-mail at theresamenard@hotmail.com.

Look for a small animal with fast-beating wings that appears to be flying erratically around sunset. They often fly about the level of a tree canopy as they track down insects using echo-location techniques. You generally won't hear them, because they make sounds for echo-location that are beyond the range of human hearing.

The Hawaiian hoary bat, Lasiurus cinereus, has been on the federal endangered species list since the early 1970s.

This small mammal is an insect-eater that roosts in trees. It is nocturnal, and generally starts feeding around sunset.

Menard said a curious factor is that the animals tend to come out as early as a half-hour before sunset in the fall, but around this time of year, when the days are longer, they come out much later. She said the Pupukea bat sighting occurred about as long past sunset as did Big Island bats she surveyed several years ago.

"The detection times were at 24 to 29 minutes after sunset," she said. "These times of detection compare well with my observations of emergence time on the Big Island, where in the month of June, I found that bats emerged (on average) 31 minutes after sunset."

Early summer is when the animals give birth. Menard said a theory is that pregnant bats are heavier and might fly slower. They could be coming out later to protect themselves from predatory birds such as hawks and owls.

"As the theory goes, one way an unmaneuverable bat could minimize predation by day-active birds of prey is to emerge under the cover of darkness," she said.

Menard has no doubt about her identification of the bat. She recently completed her master's thesis on Hawaiian bats.

"I could see the outline of (its) wings perfectly against the sky," she said. Additionally, the bat returned night after night at the same time. It was moving quickly, and the viewing time ranged from a few seconds on some nights to about three minutes on two occasions, she said.

"The bat was clearly foraging, darting after and chasing insects. It first appeared overhead flying toward the west," Menard said.

The confirmed sighting "lends credence to some of the unconfirmed sightings we've had on O'ahu," she said. There have been such reports from Makua,

Wahiawa, Hawai'i Kai and now, Pupukea.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com or (808) 245-3074.