Posts Tagged: bats

Bats: Friend or Foe?

Are bats good for the environment or are they pests? How about both? Almost all of the 25 species...

Bohart Museum Open House: What Insects Do Bats Eat?

When you watch bats emerge at dusk in the summer from the Yolo Causeway, have you ever wondered...

Mexican free-tailed bats leaving Yolo Causeway at dusk on Sept. 10, 2019. (Photo by Kathy Keatley Garvey)

Mexican free-tailed batsleaving Yolo Causeway at dusk on Sept. 10, 2019. (Photo by Kathy Keatley Garvey)

Mexican free-tailed bats ready to catch insects at the Yolo Causeway. (Photo by Kathy Keatley Garvey)

Mexican free-tailed bats ready to catch insects at the Yolo Causeway. (Photo by Kathy Keatley Garvey)

Thousands of bats nest in the Yolo Causeway during the summer. (Photo by Kathy Keatley Garvey)

Thousands of bats nest in the Yolo Causeway during the summer. (Photo by Kathy Keatley Garvey)

This is an image of a bat that Ann Holmes studies. (Photo by Shayan Kaveh)

This is an image of a bat that Ann Holmes studies. (Photo by Shayan Kaveh)

Oaks in vineyards a ‘win-win’ for bats and growers

Californians love their oak trees. During vineyard development, Central Coast grape growers often feel compelled to leave an old iconic oak standing, even if it ends up right in the middle of their vineyard. While driving through the Central Coast, it's not unusual to see the pattern of vineyard rows broken by a majestic oak tree. Aside from their beauty, what are some of the ecosystem services that these majestic trees provide?

To find answers, a UC Cooperative Extension scientist in San Luis Obispo County collaborated with a U.S. Forest Service scientist to study how bats use blue oak and valley oak trees in vineyards. UC Cooperative Extension specialist Bill Tietje, a co-author of the study, says they focused on bats that eat insects because bat populations have declined dramatically in some areas due to habitat loss and disease. “And bats don't hurt grapes. As a matter of fact, thanks to the huge number of bugs they consume—bats could be very good for a vineyard.”

To understand the potential value of remnant oak trees for insectivorous bats, the researchers placed microphones to detect bat calls within 14 Central Coast vineyards. The recordings revealed 11 species of insectivorous bats foraged within the vineyards and bat foraging activity was 1.5 times greater at the trees compared to open, tree-less areas within the vineyard. And the bigger the tree, the bigger the number of bats it attracted.

“The study results suggest that the large oak tree in my vineyard not only increases the beauty and biodiversity of the agricultural landscape, but also attracts insect-eating bats that can provide natural pest control—a win-win,” said grape grower Jerry Reaugh, who cooperated with the researchers.

In fact, the presence of insectivorous bats called woodland-adapted bats more than doubled within the vineyards with trees. The study indicates that the oak trees attracted woodland-adapted bats that would normally be absent from vineyards. 

Tietje hopes that the free insect-reduction services provided by bats will increase grape growers' incentive to manage and maintain the trees, and even to plant new oak trees in suitable areas around their vineyard, in mutual benefit to both agriculture and biodiversity.

“In addition to their value for insectivorous bats, remnant trees maintain bird and insect diversity by providing food, habitat, cover and stepping stones that facilitate the movement of wildlife within agricultural landscapes,” said Tietje.

This study comes at a time when declining blue oak and valley oak populations are of great concern.

“We hope the study will increase awareness of these beautiful and beneficial trees and make the case for conservation and restoration,” Tietje said. “Preserving and enhancing biodiversity in the midst of climate change is key to ensuring resilience in our landscapes and communities.” 

The study by University of Washington graduate student Anne Polyakov, Theodore Weller of USDA Forest Service and Tietje is published in the September 2019 edition of Agriculture, Ecosystems and Environment.

National Pollinator Week: Open house at UC Davis Bee Garden

June 18-24 is National Pollinator Week.

Do you know where your pollinators are? Think bees, birds, butterflies, bats and beetles.

And think flies. Especially syrphid flies, also known as "flower flies" and "hover flies."

The UC Davis Department of Entomology and Nematology is hosting an open house during National Pollinator Week from 11 a.m. to 2 p.m. at its bee garden, Häagen-Dazs Honey Bee Haven on Bee Biology Road, west of the central UC Davis campus.

Here's what you can expect to see or do:

• learn how to catch and observe bees up close
• see honey bees at work in an observation beehive
• learn about bee diversity and identification
• learn about what and how to plant for bees
• learn about growing and good pollination in home fruit gardens
• see easy-to-grow bee plants and solitary bee houses available for a donation to the garden.

The Häagen-Dazs Honey Bee Haven, installed in the fall of 2009 and located next to the Harry H. Laidlaw Jr. Honey Bee Research Facility on Bee Biology Road, off Hopkins Road, is a half-acre garden devoted to bee pollinator conservation and education. It was founded and sprang to life during the term of interim department chair, Professor Lynn Kimsey, director of the Bohart Museum of Entomology, who coordinated the entire project. Kimsey was singled out for her work when the Pacific Branch of the Entomological Society of America honored her and four others – "The Bee Team"– with the 2013 outstanding team award. 

A Sausalito team – landscape architects Donald Sibbett and Ann F. Baker, interpretative planner Jessica Brainard and exhibit designer Chika Kurotaki – won the design competition. The judges were Professor Kimsey; founding garden manager Missy Borel (now Missy Borel Gable), then of the California Center for Urban Horticulture; David Fujino, executive director, California Center for Urban Horticulture at UC Davis; Aaron Majors, construction department manager, Cagwin & Dorward Landscape Contractors, based in Novato; Diane McIntyre, senior public relations manager, Häagen-Dazs ice cream; Heath Schenker, professor of environmental design, UC Davis; Jacob Voit, sustainability manager and construction project manager, Cagwin and Dorward Landscape Contractors; and Kathy Keatley Garvey, communications specialist, UC Davis Department of Entomology and Nematology.

Others with a key role in the founding and "look" of the garden included the UC Davis Art/Science Fusion Program, founded and directed by the duo of entomologist/artist Diane Ullman, professor and former chair of the UC Davis Department of Entomology, and self-described "rock artist" Donna Billick of Davis. Miss Bee Haven, a six-foot long worker bee sculpture, the work of Billick, anchors the garden. The art in the garden is the work of their students, ranging from those in Entomology 1 class to community residents. Eagle Scout Derek Tully planned, organized and built a state-of-the-art fence around the garden.

Why are pollinators so crucial? Take it from the Xerces Society for Invertebrate Conservation:

"Pollinators are essential to our environment. The ecological service they provide is necessary for the reproduction of over 85 percent of the world's flowering plants, including more than two-thirds of the world's crop species. The United States alone grows more than 100 crops that either need or benefit from pollinators, and the economic value of these native pollinators is estimated at $3 billion per year in the U.S. Beyond agriculture, pollinators are keystone species in most terrestrial ecosystems. Fruits and seeds derived from insect pollination are a major part of the diet of approximately 25 percent of all birds, and of mammals ranging from red-backed voles to grizzly bears. In many places, the essential service of pollination is at risk from habitat loss, pesticide use, and introduced diseases."

So, on Saturday, June 23, you won't see any red-backed voles or grizzly bears. But you'll see bees, butterflies, birds and beetles.

And flies. Syprhid flies.

For more information on the open house, access https://hhbhgarden.ucdavis.edu/wp-content/uploads/2018/01/Pollinator-week-flyer-2018-1.pdf

 

Bats, allies to farmers, return home to roost in spring

Bats, those night-flying creatures of horror film fame, are beginning to migrate back to the Central Valley. It is an annual journey for most bats, flying south for the winter and returning home in the spring to their birth place to roost and give birth to their own pups during the summer.

“I'm getting a number of calls from people who see bats and are worried about them,” said Rachael Long, UC Cooperative Extension advisor for Sacramento, Solano and Yolo counties. “If people see bats on the ground or tucked into eaves, they're likely resting, not sick, from their long migration north.”

Because the insect-eating winged mammals are important allies to U.S. farmers, Long hopes people won't harm the bats while they are tired and vulnerable. Bats feed on some of the most damaging crop pests – including the moths of cutworms and armyworms – which helps to protect food crops naturally.

Farmers appreciate the pest control provided by bats and many look forward to having bats return to their farms each year, according to Long, who coauthored a study of farmer perceptions of wildlife recently published online in Conservation Letters, a journal of the Society for Conservation Biology.

“Most of the farmers surveyed reported that they like bats and the pest control and crop protection services they provide,” Long said. “Many put up bat boxes on their farms to provide a home for them.”

In their long journey north, bats need to rest along the way. Sometimes they turn up in areas where they're not wanted, such as in a corner of a porch or in an eave. The presence of bats is often revealed by their mouse-like droppings, or guano.

“In the sun, the guano sparkles, as it's made of bits of insect parts, making it a good source of nitrogen for plants,” Long said.

Bats live for about 30 years and bear only one pup a year. Males roost independently of females and their pups, so if you see a lone bat, it's likely a bachelor.

“If you find a bat, please leave it alone if it's not bothering anyone because it may be perfectly healthy, just tired,” Long said. “A farmer somewhere may be waiting for that bat to come home to help protect crops from insects.”

If you see a bat on the ground, Long suggests placing a box over it and calling a wildlife rescue organization, such as Northern California Bats in Davis. She recommends wildlife rescue because animal control officers must euthanize all bats they catch to test for rabies, which may be unnecessary unless a person or a pet had contact with the bat.

 

Further reading:

Migrating bats may be resting, not sick, says UC bat expert

Farmer Perceptions and Behaviors Related to Wildlife and on-farm Conservation Actions

UC Integrated Pest Management Pest Note on Bats

Read more