Whistler’s bat (and moth) world — episode two
Last week I wrote briefly about some of the basic biology of two common bats likely found in the Whistler area: Big and Little Brown Bats. These days, thanks to research and educational programs, most people do know the basics about bat biology — bats are mammals, giving birth to live young which are nurtured by their mother’s milk until they are able to fly on their own. Bats in the Whistler area feed on night-flying insects. Big Brown Bats feed on moths and beetles, and smaller Little Brown Bats seek out mosquitoes and other little insects.
But how on earth do they accomplish this — at night, in flight, without hands or paws for grasping, or light to see their prey by? Biologists believe that bats were probably the first animals to develop the ability to use ultrasonic echolocation to find their prey, and to navigate their way around trees (and buildings) in the night sky.
Bats make some noises that are audible to human ears, little squeaks probably used to communicate from mother to pup. Bats also send out high-frequency calls not audible to human ears. Those calls bounce back as an echo, which the bat’s sensitive ears can clearly detect. The echo is interpreted by the bat’s brain as a ‘map’ of an area, allowing the bat to ‘see’ obstacles and small prey items in flight. They then pursue their victims, scooping prey into their mouths using their tails or wings.
But it’s not that simple. Some moth species have developed the ability to detect a bat’s feeding call and will immediately drop to the ground to avoid a pursuer, or will suddenly begin to fly erratically and chaotically to outmaneuver the bat in pursuit. The result is an amazing moth vs. bat aerial ‘dog-fight’ display (look for this at night around streetlights near creeks or lakes).
I could write paragraph after paragraph extolling the amazing feats of these little flying mammals, but instead I invite you to an evening of bat facts and fun. Join the Whistler Naturalist Club for a special bat program, from 7 p.m. to dusk. We will meet a local bat and learn more about bats found in Whistler (Do they bite? Are they dangerous? How do I get them out of my attic or house? Can they spread disease? Where can I see them?). We will build some bat houses (small materials fee), and we may even be lucky enough to see and hear some bats at Green Lake.
Bring a lawn chair, a thermos of hot drinks, a flashlight and warm clothes. It will be fun, informative and the best darn value for your dollar in town. For information on the location and material costs, and to let us know you would like to attend, please call Cathy.
For a great website with information on bats (and birds, and plants, and …) check out the on-line nature encyclopedia ‘NatureServe’ at www.natureserve.org. This top-quality website should be on everyone nature lover’s favourites list.
Upcoming Events :
June 16 — Bat Night . Come out, learn about bats, and build your own bat box. Meet at the front door of the high school at 7:00 p.m.. See additional details in the column above. Children welcome. There will be a charge of $15 to cover the cost of materials for those wanting to build a bat box.
June 19 — Sunset Nature Walk . Shadow Lake Interpretive Forest. Meet at 7:00 p.m., approximately 13 kilometres north of the Alpine Meadows traffic lights, on the east (right) side of the road. Watch for a sign reading "Shadow Lake Interpretive Forest 400 metres". Free for members; $2 for non-members. Call Bob Brett for more information or to arrange car pooling.
Our bird walk at One-Mile Lake last Saturday was terrific. Forty-seven species of birds, lots of great plants, and excellent leaders in Kevin Bell, Max Gotz, Barry Janyk, and Dave Aldcroft (here for the Breeding Bird Survey). Thanks to them and all the keen naturalists from Pemberton. Huge thanks to Gordon McKeever and Rainbow Rentals Accommodation for putting a roof over our visitors’ heads. Also, heartfelt thanks to Drs. Collins and Fisher from the Pemberton Clinic who made sure our sick birder was well cared for. He’s made a full recovery.
Written by: Cathy Conroy