Ah, the call of the wild. Sometimes it is silent. But this does not prevent wildlife researchers Patricia Ormsbee and Joe Szewczak from detecting it.
The researchers are adept at detecting some of nature's sounds of silence. They demonstrated how it is done last week in Union County.
The scientists are helping conduct a bat research project in Oregon aimed at determining precisely which types of bats live in the state and how they are distributed.
One of the best ways to identify bat species is by analyzing their calls. Bats bounce high frequency sounds off of objects to determine where things are called "echo locating.''
These vocalizations are usually impossible to hear because most echo-locating bat calls are emitted at a frequency too high for the human ear.
Enter Ormsbee, a U.S. Forest Service wildlife ecologist from Eugene, and Szewczak, a biology professor at Humboldt State University in Northern California.
They are detecting bat echo-locating calls with the use of an ultrasound recorder. Ormsbee and Szewczak demonstrated their ultrasound recorders last week in Union County.
Their objective was to train biologists in Northeast Oregon to help with the bat study.
The biologists received training during the day, and then were led by Ormsbee and Szewczak on missions in the evening. They traveled to forest sites where they set up nets in areas where bats might be expected to fly. Bats caught in the nets were then tested for their echo-locating calls.
The bats that were caught were put into an elastic harness attached to a zip-line. The bats then flew down the zip-line while their echo-locating calls were recorded.
These sounds are different from those bats make while communicating in colonies, Szewczak said. Socialization calls are at a lower frequency and can be heard by humans, but they do not identify the species in the way echo-locating vocalizations do.
Ormsbee said the information being gathered will also help determine which habitat is most suitable for each bat species, information necessary to help bats survive.
Szewczak said that ultrasound recorders are helping researchers make significant strides and fill information voids that had long existed.
"We have had huge gaps of understanding (of bats),'' Szewczak said. "We have not had the tools we've needed."
Szewczak has handled numerous bats since the study started. The biologist is finding that bats of the same species can vary significantly in terms of personality.
"They have different temperaments, and tend to be unique from individual to individual,'' Szewczak said. "I view this as an indication of intelligence.''
Ormsbee is leading the study of Oregon's bat populations. The study involves the U.S. Forest Service, the Oregon Department of Fish and Wildlife, the Bureau of Land Management, the U.S. Fish and Wildlife Service and Bat Conservation International.
Bats can be trained, according to Joe Szewczak, biology professor at Humboldt State University. Szewczak said bats have been taught to fly around rooms and then land at specific places. "Bats can be trained to respond to commands,'' he said.
Ten millennium legacy?
A mummified bat was found in a bat colony in the Southwestern U.S. Tests indicated that the mummified bat was 10,000 years old, Szewczak said. Scientists also found that the mummified bat had the same genetic make-up as the bats that come there today. It is not known, though, if bats have been using the site continually for 10,000 years.
Never tire of insects
Some bats eat as many as 600 mosquitoes an hour.Their insect diet also includes moths and crickets, according to the Texas Parks and Wildlife Web site.
Little big bats
The bumblebee bat in Thailand is the world's smallest. It weighs no more than a penny. On the other end of the scale, the giant flying fox, in nearby Indonesia has a winspan of nearly six feet.
Rulers of the world?
With well over 1,000 species, bats make up one quarter of all mammals on earth.
Fruit bats are cruicial for pollination and seed dispersal for bananas, breadfruit, mangoes, cashew, dates and figs.