Severe Weather Takes Heavy Toll in Texas

By Merlin Tuttle
3/2/21

Given overall warming trends, we weren’t surprised to see some 70 to 80° F days in January and February of 2021. But that hardly tells the full story!

Beginning on February 10th, historically low temperatures were recorded across Texas. For eight consecutive days (February 10–18), the temperature hovered between 37° and 9° F with six inches of snow on the ground in Austin, Texas. The first reasonable feeding opportunity for bats likely didn’t occur before the 21st.

The last similar event occurred 32 years ago in 1989. In a 9-day period (December 16–24) the daily temperature ranged from 51 to 4° F but remained below freezing for only two days versus seven in 2021. Fewer people were concerned in those days, but at least hundreds of killed bats were reported.

Brazilian free-tailed bats about to emerge from their day roost in a bridge crevice in Austin, Texas.

The recent event, Winter Storm Uri, created a disaster for overwintering Brazilian free-tailed bats (Tadarida brasiliensis). Encouraged by warming trends, more and more bats have remained in their summer roosts year-round instead of migrating south for winter. In recent years, hundreds of thousands have overwintered in bridge crevices of Central Texas, especially in the Austin area. Additionally, over the last four decades, an estimated 1,000 more annually have remained in Bracken Cave.

Unlike many other temperate-zone bats, Austin’s free-tails are not true hibernators. They do store fat in the fall and can survive for more than six weeks without feeding when roosting at 41° F. In Central Texas, they emerge and successfully feed when evening temperatures are 50° F or above, and in traditional winters they seldom would need to wait more than 10 days between feedings.

To survive for eight days with average temperatures well below freezing would be an extreme challenge. Bats have the largest surface area per volume of any warm-blooded animal, and active free-tails maintain body temperatures of roughly 102° F. Following the recent weather crisis, just warming up to go hunting was undoubtedly prohibitive for many, and it’s difficult to imagine that the insects the bats depend on for food would have been immediately abundant. Even though daytime temperatures averaged 78° F over four consecutive days beginning on February 21st.

Many concerned Austinites wondered why accumulations of dead and dying bats steadily grew through at least the 25th, despite the return to warm weather. The answer is two-fold. Many bats likely were still alive but too weakened to go hunting. Some of those may take a week or more to die. Also, those that literally froze to death could take weeks to fall from their roosting crevices. Tendons in their toes are designed to automatically lock the bats’ claws firmly to the roosting crevice until consciously released. Thus, a bat may hang in place long after its death

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Exploring Ecuador’s Los Cedros Reserve

4/15/2020
By Teresa Nichta

This rainy February, we visited Los Cedros Biological Reserve in Ecuador.

Roo Vandegrift, and crew, are filming Marrow of the Mountain; a documentary about the mega-mining now in Ecuador. “In 2017, the amount of land available for mining expanded by hundreds of percent, leaving huge swaths of Ecuador’s most sensitive and biodiverse habitats at the mercy of international mining interests. These concessions appeared suddenly and were sold without public knowledge or consent, especially affecting the mineral-rich and endangered Choco Rainforest.” Roo invited MTBC to conduct a bat survey, which could support litigation to stop the illegal gold mining and help protect the reserve’s unique flora and fauna. The data is to track diversity and endemism at Los Cedros, and analyses are submitted to conservation groups and government agencies, like Critical Ecosystem Partnership Fund and the Ecuadorian state Institute for Biodiversity (part of the Ministry of Environment).

Los Cedros Biological Reserve consists of 17,000 acres of premontane wet tropical forest and cloud forest. Of this, 2,650 acres is formerly colonized land, while the remainder is primary forest. The reserve is a southern buffer zone for the 450,000-acre Cotocachi-Cayapas Ecological Reserve, and both are part of the Choco Phytogeographical Zone. The Choco region is one of the most biologically diverse and endemic habitats on Earth.

Part of its charm is the journey to get there. Monica and I left our Quito AirBnB at 5 am to board a 3-hour long bus ride to Chontal, where we met Marc Dragiewicz of Eyes of the World Films. It was then just a short 30-minute truck ride to the trailhead. 

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A Model Example of Bat Recovery Potential

By Merlin Tuttle
9/25/19

Long Cave, in Kentucky, like many others, has a long history of human occupation with little record of prior use by bats. It was mined for saltpeter, a key ingredient of gun powder, during the war of 1812 and was subject to commercial tourism, probably beginning at about the turn of the century, ending by the 1930s.

Rick Toomey and Merlin Tuttle waiting for group to enter bat-friendly gate at Long Cave.

Huge passages trapped cold air and remained cool year-round, offering major opportunities for bat hibernation. Roost stains from past bat use were widespread, and the cave clearly had potential to shelter millions. As recently as 1947 some 50,000 bats, presumed to be largely the now endangered Indiana myotis (Myotis sodalis), continued to return in winter. Nevertheless, entrance barriers built to exclude non-paying tourists, increasingly restricted air flow, eventually culminating in a concrete wall and a nearly solid door.

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Partnership for Bat Conservation and Management Training

9/19/18
By Merlin Tuttle

John Chenger and Julie Zeyzus interviewing Merlin for training video on bat cave management.

In early August, we accepted a partnership invitation to develop a series of bat conservation and management training videos. Though growing numbers of biologists are studying bats, few have the breadth of experience essential to meet their widely varying conservation needs. Each species has unique requirements. In order to better share my nearly 60 years of personal experience, John Chenger founder of Bat Conservation and Management, and Janet Tyburec founder of Bat Survey Solutions, invited me to collaborate. They are providing video shooting and editing, featuring my narration and illustrations.

Teresa Nichta (left) and Julie Zeyzus shooting slow motion video of Brazilian free-tailed bat (Tadarida brasiliensis) emergence.

 

 

 

Four programs are now being edited. The first, tentatively titled “Win Friends, not Battles,” explains key approaches that have most effectively won long-term cooperation. The second features the worldwide importance of bats. The third addresses greatly exaggerated disease claims, and the fourth deals with assessing cave suitability for bats and special long-term management needs.

Bad gate that caused abandonment by a large colony of cave myotis (Myotis velifer). New owners removed the gate, and the bats are now gradually returning.

Under John’s guidance, we began field shooting on August 15, greatly aided by Teresa Nichta and John’s associate, Julie Zeyzus. For the next 10 days there was little time for sleep or even eating. On my birthday, we spent seven hours filming underground, a great antidote for thinking of getting old!

Measuring roost stains left by a formerly large colony of cave myotis in a Texas cave. Stains can last for centuries, providing an invaluable estimate of past colony size.

 

Illustrating the need for such education, one of the caves we visited in a protected nature reserve, had lost its entire colony of tens of thousands of cave myotis when fire protection permitted entrance blockage by vegetation. Another cave, also well protected by its owner, had overgrowth of an invasive, introduced plant that could have prevented restoration of a formerly large colony. It only took minutes to eliminate the threat.

 

 

 

 

Videoing Brazilian free-tailed bats close-up in crevices between box beams.
Explaining how bat-friendly bridge designs have aided Texas farmers.
Sunset emergence of free-tailed bats.

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Counting Free-tailed Bats in Bridges

9/10/18
By Merlin Tuttle

Merlin inspects Brazilian free-tailed bats (Tadarida brasiliensis) moments after removing them from their bridge crevice roost for counting.

For many years we’ve wondered just how many Brazilian free-tailed bats (Tadarida brasiliensis) could cram into a single 18-inch-deep bridge crevice. Accurate counts of large colonies are difficult no matter how they’re made. However, when estimating bridge colonies, it would help if we knew the number, using an average horizontal foot of crevice.

The solution seemed easy. Two years ago, Glen Novinger, an MTBC member and I, inserted two, three-quarter-inch-thick wooden frames, each encompassing a square foot of interior space, into bridge crevices of the same width while the bats were out feeding. The idea was to later slowly remove them, forcing those roosting inside to exit into a cloth-lined bag from which we would count them.

However, the bats were full of surprises. The first night we waited patiently till half an hour after we’d seen the last ones leave—or at least that was what we thought! But when we approached to install our devices, roughly half remained inside. I couldn’t help but wonder how many emergence counts had missed those that, for whatever their reasons, didn’t emerge at sundown. (more…)

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Success in Panama!

During both weeks of our workshops, we encountered periodic rain showers, keeping the normally hot, dry-season temperatures far more comfortable than anticipated. The downside was that we had poor netting results on three nights during the second week. We shared the forest with some interesting characters, such as a black jaguar, which fortunately left us alone, though it likely observed our activities. This one was photographed on a trail camera near one of our netting sites.

 

We set up a triple-high mist net almost every night, both weeks.

Departing to net bats over the nearby river. Daniel Hargreaves is carrying the triple-high net rig in the red bag. His team of skilled instructors from the U.K., Steve and Fiona Parker and Daniel Whitby, were superb.

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More Bats from Cocobolo

During our two-week stay in Panama’s Cocobolo Nature Reserve, we recorded more than 600 bats of 53 species, more than half the total number known for the entire country. Additional species were netted nearly every night, including two on our final evening. Over our two-weeks of workshops, common vampire bats (Desmodus rotundus) and greater fishing bats (Noctilio leporinus) were participant favorites, though an incredible variety of fruit-, nectar-, and insect-eating species were seen. The hardiest of our group members often worked till dawn, bringing in a steady stream of species for portrait photos, especially during the first week. By the second week much more time was devoted to training bats to come on call, especially to locations where Merlin could photograph natural behavior, such as catching katydids.

Merlin Tuttle training a hairy big-eared bat (Micronycteris hirsuta) to come on call to a leaf to catch katydids (its natural prey) in front of bright video lights needed for high speed video shooting.

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Some non-bat Cocobolo critters

We found dozens of creatures while out netting for bats, and even at base camp. We don’t have species names for all of them but here’s a small collection of some of Cocobolo’s non-bat critters…

 

Jen Shallman with a Mussurana snake (Clelia clelia) Photo: Los Naturalistas
Gladiator tree frogs (Hypsiboas rosenbergiPhoto: Los Naturalistas
Eyelash viper (Bothriechis schlegeliiPhoto: Los Naturalistas
Brown blunt-headed vine snake (Imantodes cenchoaPhoto: Los Naturalistas
Photo by Daniel Whitby
Photo by Daniel Whitby
Photo by Daniel Whitby
Photo by Daniel Whitby
Photo by Daniel Whitby
Photo by Daniel Whitby
Bullet ants Photo by Daniel Whitby
Kind toad Photo by Daniel Whitby
Photo by Daniel Whitby
Photo by Daniel Whitby
Photo by Daniel Whitby
Photo by Daniel Whitby
Photo by Daniel Whitby
Whip scorpion Photo by Daniel Whitby
Photo by Daniel Whitby
Coral snake (Mircrurus clarkii), this was the first one of this species ever seen on Cocobolo Nature Reserve! So many discoveries to be made here.

 

 

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MTBC’s Bat Adventures continue: Panama – Week 2!

The new group arrived successfully and with bells on for Week 2.

We have three bats in training. Merlin trained a hairy big-eared bat (Micronycteris hirsuta) for photography. Within 15 minutes it was flying to his hand on call, rewarded with meal worms. Janell Cannon, the famous author of  Stella Luna, trained a white-throated round-eared bat (Lophostoma silvicolum) to eat from her hand. Her bat has a very calm temperament. Alexis and Amy trained a Niceforo’s big-eared bat (Trinycteris nicefori) for photography, a very sweet and eager gal.

Merlin guiding Janell in training the (Lophostoma silvicoluma) in a small tent provided for this purpose.
Merlin guiding Janell’s bat training.
Merlin guiding Alexis in training a (Trinycteris nicefori).

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Bats from Cocobolo

We’re just finishing up an incredible first week at Cocobolo and already caught 44 species of bats, everything from fishing bats to vampires, not to mention a wide variety of fruit, nectar, and insect eaters. Merlin added 10 additional species to his collection! Pygmy fruit-eating bats were found roosting in leaves they had cut to form “tents”.

Pygmy fruit-eating bat (Artibeus phaeotis)

Chestnut short-tailed bats were all around camp, feeding on piper fruit.

Chestnut short-tailed bat (Carollia castanea)

We caught more than 20 Common vampire bats. Frontier campesinos keep a few livestock not too far away, explaining the presence of so many vampires. Most of these seem to have lots of personality, enabling Merlin to get this cool photo. The trip participants had loads of fun shooting videos of the vampires running around on the ground on all fours.

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