Bats in Leiden in The Netherlands

This video from Spain is about a Pipistrelle bat, Pipistrellus pipistrellus.

In Leiden in The Netherlands, there are various species of mammals.

They include seven species of bats.

The most common species is the pipistrelle bat, seen over 400 times in 2004.

Other species: Nathusius’ pipistrelle bat; serotine bat; brown long-eared bat; noctule bat; the two last-named species in the Leidse Hout.

Close to water: Daubenton’s bat, and Myotis dasycneme (see also here).

Bats in Britain: here.

Gray Myotis bats: here.

Myotis emarginatus: here.

Bat protection: here.

Caribbean bat evolution: here.

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1 thought on “Bats in Leiden in The Netherlands

  1. Study finds fewer bats, big impact

    As freetails dine across Texas, their bug diet saves farmers $1.7 million a year

    11:47 PM CDT on Sunday, July 8, 2007

    By DAVID McLEMORE / The Dallas Morning News

    UVALDE, Texas – Just as the sun collapses into a ball of fading color in the western sky, bats stream out of Frio Cave in two twisting columns with a sound like running water.

    Nightly, this colony of freetail bats leaves the cave – an expansive geological formation carved out of a limestone hill on a private ranch about 25 miles north of Uvalde – in search of a late-night snack.

    At the same time, millions of bats from 11 other major caves scattered across the eight-county South Texas agricultural area known as the Winter Garden fill the sky in such numbers that they appear as storm clouds on weather radar.

    Researchers have long known that bats in Texas caves dine on insect pests. But just how many bats there are and the value of their feeding had proved elusive until a five-year, $2.4 million National Science Foundation study by scientists from Boston University, the University of Tennessee, the U.S. Department of Agriculture and Texas Parks and Wildlife.

    From sundown to sunup, the freetail bats consume a staggering 400 metric tons of insects a year in the Winter Garden, or 2 million pounds each night. They range over a radius of 75 miles and feed from ground level to 10,000 feet.

    The bats help save $1.7 million annually by preventing crop damage and additional pesticide use in the eight-county Winter Garden, which produces $6 million in cotton each year, according to the report by the Boston University team.

    “Most people think of bats as ugly or vile, but there is a real value they provide humankind,” said principal investigator Tom Kunz of Boston University. “The bats are a literal shield for this crop region. But until this project, no one developed a means to measure the specific economic value of bats to agriculture.”

    Scientists were also surprised to learn there are far fewer bats than long believed.

    The 8 million once believed setting up shop in Frio Cave is closer to 2 million. At the Eckart James River Cave near Mason, digital enhancement of infrared photos of the bats’ nightly departures, audio analysis of their feeding calls and software that lets scientists track multiple bat trajectories provided a count of 1.4 million, instead of the estimated 6 million.

    “But a million bats is still a lot of bats,” Dr. Kunz said.

    Follow that moth

    And the economic value of bats is not restricted to South Texas, according to John Westbrook, Agriculture Department meteorologist and a co-principal investigator on the research team.

    The bats’ main diet – the corn borer moth and another delicacy, the tobacco budworm – costs farmers $1 billion each year nationwide in ruined crops. Freetail bats follow the corn borer moth from Mexico, intercepting them in farm fields before they can migrate and infest fields in North Texas and on into the Corn Belt in the Midwest.

    At Frio Cave, Gary McCracken of the University of Tennessee, and a co-principal investigator, pauses in his nightly labor to give an impromptu lecture to a family from Houston on the value of bats.

    “Each of these little guys weighs as much as a penny, yet they’ll eat up to 70 percent of their body weight each night,” he says. “That’s a lot of worms that won’t be eating more crops or laying eggs to create more worms.”

    Jimmy Stallons and his family interrupted a camping trip at nearby Garner State Park to see the bats. The ranch owner opens the cave to visitors during the summer.

    “This is my first time to see a bat cave, and I can’t believe it,” Mr. Stallons said. “They zoom out of that cave and there doesn’t seem to be an end to them. It’s just amazing.”

    Bat detectors

    Dr. McCracken has spent the past 25 years studying bat life in South Texas. His part of the National Science Foundation study is to examine the extensive range of the bats with a series of audio bat-detectors set up in 15 fields scattered across the Winter Garden.

    Microphones, attached to small computerized computers, are attached to PVC pipe that rises 10 feet above fields of corn, cotton, maize and wildflowers. They catch the high-pitched ‘cheep-cheep’ echo-location calls the bats make to let their hunting mates know where they are, as well as notify the column where the moths are.

    “When they sense a field of corn-borer moths, the frequency of their calls increases faster and faster,” Dr. McCracken said. “It’s like a dinner bell. Then it turns into a real feeding frenzy.”

    At different locations, Dr. McCracken and his research assistants also set up “poop catchers” – wood-and-screen structures, covered with a sticky substance – to collect evidence of just what the bats eat.

    “It’s the merger of low-tech with high tech,” he said. “But the samples we collect provide definitive evidence that about 70 percent of the feeding volume for bats is the corn borer moth.”

    The catchers also record what Dr. McCracken delicately calls the “fecal rain” that helps enrich the soil of the agricultural region.

    “When you have millions of bats, each eating up to 70 percent of their body weight each night, that’s a lot of soil enrichment,” he said.

    Dr. McCracken pauses to watch the bats rush out, flickering specks against the dying light of the day.

    “After 25 years, it’s still something I never get tired of watching,” he said.


    Bat-watching sites in Texas

    1. Bamberger Ranch Preserve: about seven miles south of Johnson City; the world’s first and only man-made bat cave. Tours offered Friday evenings, June through September; reservations must be made in advance; 830-868-2630 or

    2. Bracken Cave and Nature Reserve: on the northern outskirts of San Antonio; the world’s largest bat colony. Owned by Bat Conservation International and open only to its members;

    3. Clarity Tunnel: on the trailway of Caprock Canyons State Park, southeast of Amarillo; an abandoned railroad tunnel. Tours offered Friday evenings, June through September; 806-455-1140 or 806-455-1492

    4. Congress Avenue Bridge: downtown Austin; the world’s largest urban bat colony. Reservations are not needed for free viewing, boat viewing is offered nightly, March through October; 512-416-5700, category 3636 or

    5. Devil’s Sinkhole State Natural Area: north of Rocksprings on U.S. Highway 377. Visitors Center open 10 a.m. to 4 p.m. every day April through October, closed Mondays November through March; reservations must be made in advance; 830-683-2287 or

    6. Eckert James River Bat Cave Preserve: 17 miles south of Mason near the James River. Open 6 to 9 p.m. Thursdays through Sundays from mid-May to early October; 325-347-5970

    7. Frio Bat Cave: east of U.S. Highway 83, just south of the Frio River. Privately owned, open mid-March through September, reservations must be made in advance; 830-966-2320 or

    8. Old Tunnel Wildlife Management Area: about 10 miles southeast of Fredericksburg. Owned by Texas Parks and Wildlife, open year-round sunrise to sunset, group tours available by reservation on Monday-Wednesday evenings; 866-978-2287

    9. Stuart Bat Cave: at Kickapoo Cavern State Park, 22 miles north of Brackettville on FM674. Owned by Texas Parks and Wildlife, reservations are needed, park is open various hours; 830-563-2342

    10. Waugh Drive Bridge: over Buffalo Bayou about 10 miles west of downtown Houston. Owned by the city of Houston, open year-round, reservations are not needed; 713-845-1000 or


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