Adventures with Bats: Conservation of Canada’s Flying Mammals

I’ve been a little bit bat crazy ever since reading the Silverwing series as a kid. But more recently my bat love has turned from reading about them to working with real live bats! Last week I had the opportunity to help with mist netting project for bats in Ontario. I’ve assisted with mist netting in Costa Rica and really fell in love with bats while I was there. What I took away from my experience in Costa Rica was that the bats of North America, particularly Eastern North America, are in trouble! I learned a little bit about white nose fungus, which can be a fatal problem for bats and is currently spreading into and across Canada.

A little brown bat, very common in Southern Ontario - Photo by Christy Humphrey

A little brown bat, very common in Southern Ontario – Photo by Christy Humphrey

Most people don’t realize how large of a role bats play in our ecosystem. They are responsible for seed dispersal, pollination, and some serious insect control. Like, 1,000 mosquitoes per hour insect control! Even as someone who loves animals I can appreciate a hatred of mosquitoes. Bats also pollinate agave plants, which are used to make tequila. So when you think about bats, think about drinking tequila outside while not being bitten by mosquitoes. Just picture that for a moment…Now hopefully you’re on board with saving the bats! Which we’ll come back to in a moment.

Save the bats, save the tequila.

Save the bats, save the tequila.

Outside of a known roosting site, a church in Southern Ontario, we set up some large mist nets (mist nets look like volleyball nets, but are made with very fine mesh the bats have a difficult time detecting). This was luxury mist netting, in Costa Rica we set up our nets across paths in the jungle! We counted over 200 bats flying out of the roost and caught 38 of them. The studies I assisted with in Costa Rica were purely population dynamics: identify, record gender and species and let them go. This was a little more invasive. We held the bats until they were processed and then released them.

A bat caught in a mist net. As long as you are diligent about checking the nets frequently they don't get too tangled. Photo by Stuart

A bat caught in a mist net. As long as you are diligent about checking the nets frequently they don’t get too tangled. Photo by Stuart

Processing involved weighing, measuring the wing, banding with an individual ID tag, checking for scarring on the wing (evidence of white nose fungus), taking a small sample of tissue from the wing for DNA analysis (surprisingly this did not seem to disturb the bats based on their lack of reaction), and taking a small hair sample for molecular analysis of metals.

Placing a lightweight band on a little brown bat - Photo by Christy Humphrey

Placing a lightweight band on a little brown bat – Photo by Christy Humphrey

The primary purpose here was to monitor for white nose fungus. This fungus was first recorded outside of New York in 2007 and has since spread up to 2,000 km away, infecting bats in many Eastern states and provinces. As of 2013 the fungus has been confirmed in bat populations as far West as central Ontario in Canada and Western Missouri in the US.

A distribution map of white nose fungus from whitenosefungus.org

A distribution map of white nose fungus from whitenosefungus.org

White nose syndrome is named for the appearance of a white fungus on the face - Photo by US fish and wildlife services

White nose syndrome is named for the appearance of a white fungus on the face – Photo by US fish and wildlife services

This fungus causes bats to behave strangely, coming out of hibernation in the winter which results in excess energy being used and an inability to survive the winter. Approximately 50% of little brown bats in an affected colony will die over the winter in an affected colony. 90-100% of bats in some regions have died. In Southern New Brunswick, an area boasting a population of 7,000 bats in 2011, the estimated population is 22 bats in 2014. That is not a typo. Twenty two bats!

The fungus causes damage to the wings, and even those who survive the winter often have extensive scarring on the wings. - Photo by US Fish and Wildlife Services

The fungus causes damage to the wings, and even those who survive the winter often have extensive scarring on the wings. – Photo by US Fish and Wildlife Services

Stopping, or at least slowing, the spread of this fungus is extremely important. Bats are important everywhere, but our Westernmost province has the most to lose. With 16 species of bats (including 8 endemic species) found in British Columbia, half of which are either red or blue listed, BC would be hit hard by this fungus.

Cavers are very important in helping to stop the spread of this fungus! If you enter a cave, after ensuring it is safe and not closed due to conservation reasons, always wash everything you were wearing/using before entering another cave. Humans moving between roosting sites, mostly while caving, have been the main factor in spreading this fungus. You can report any strange behaviour in bats (ie. flying around in the middle of the winter) to the local natural resource agency, build a bat box to provide a roosting site for bats (plans can be found online), and not disturb hibernating bats. See other suggestions on how you can help bats here: https://www.whitenosesyndrome.org/what-can-you-do-help

There are many myths out there about bats, but once you get past all of the bad media they are amazing creatures and very necessary for our ecosystem to thrive and survive! We need these little creatures to stick around, so try your best to love the bats. When in doubt, think of the tequila.

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Nature’s Engineers: Bird Nests

Animals have been building nests for millions of years, there are even fossil records of dinosaur nests! Over time nests have become very complex and from birds to turtles to termites and wasps there is beauty, diversity and much to be learned from these structures!

When we hear the word “nest” we tend to think of a standard woven cup structure built by a song bird of some sort, but there is an amazing amount of diversity in nests; materials, shape, strength, size that we don’t necessarily think about.

There is quite a bit of evidence for evolution in bird nests. Some ground nesting birds don’t build nests at all, others make small depressions by rubbing their breast into the ground. Some birds make stick nests either on the ground or in trees and others weave together materials into some of the more complex animal built structures. Birds are always competing for resources, and nest materials are no exception. To deal with competition for nest materials some birds use specific materials or habitats not utilized by other species for nesting. Using different materials can sometimes require some creative engineering, and we end up seeing some amazing structures as a result, such as the hanging nest of the Montezuma Oropendola:

The Montezuma Oropendola weaves a hanging basket using sturdy vines attached to overhanging branches. It continues to add smaller wines and other fibrous material until the basket is complete. These birds utilize the environment by nesting in areas with hornets in them! The honets deter cowbirds, who often lay eggs in the Oropendola nests.  Photo by  Amy Evenstad

The Montezuma Oropendola weaves a hanging basket using sturdy vines attached to overhanging branches. It continues to add smaller wines and other fibrous material until the basket is complete. These birds utilize the environment by nesting in trees containing hornets! The honets deter cowbirds, who often lay eggs in the Oropendola nests. Photo by Amy Evenstad

The Great Crested Flycatcher will often weave a snake skin into it's nest

The Great Crested Flycatcher will often weave a snake skin into it’s nest (2)

A particularly interesting example of creative uses of materials to build a unique structure suited perfectly to utilize an environment uncommon for nesting is the cliff swallow.

A cliff swallow leaving it's nest: a mud based structure on the side of overhanging cliff faces, man made structures such as houses and the occasional tree. Photo by Jerry Kirkhart.

A cliff swallow leaving it’s nest: a mud based structure on the side of overhanging cliff faces, man made structures such as houses and the occasional tree. Photo by Jerry Kirkhart.

There are not many birds who a. nest on cliff faces and b. utilize mud as a primary building material. The cliff swallow is really taking advantage of a niche market. Even between Cliff and Barn Swallows (another mud utilizing nest builder) the mud composition is different, so the two species are not competing over the same mud. This likely contributes to the differences in nest shapes between the species. Barn swallows build a more cup shaped nest while the cliff swallows build a dome. Cliff swallows (both male and female) will collect mud pellets from alongside bodies of water and place them on a vertical wall, under overhanging structures to create a nest composed of 900-1,200 individual pellets of mud! They will often also add plant fibers and hair to the structure, then line the inside with feathers and other softer fibers.

Cliff Swallows will nest in groups of up to 1.000 individuals!

Cliff Swallows are very social when it comes to nesting, and will nest in groups of up to 3,700 nests! A great way to deal with predators of other species, but sometimes this results in nest parasitism, where one bird will lay it’s eggs in another bird’s nest.

It takes 1-2 weeks for the Cliff Swallow to build it’s nest, which all things considered is actually rather fast! This structure has no load bearing capabilities from below, yet will support 4-6 eggs for 12-14 days and once hatched, nestlings will remain in the nest for 23 days. The design of the cliff swallow nest has been studied by engineers and shown (in engineering terminology I don’t completely understand, but appreciate due to the parts I can understand as well as trust in the peer review process) to have a nearly perfect design for it’s use!

Basically what I’m trying to say is that bird nests are amazing. From the ground nests of penguins, to goldfinch cups, mourning dove, chipping sparrows and cliff swallows. Nature’s engineers are hard at work creating amazing structures in which to raise their young.

Mourning doves create a rather flimsy platform of twigs, sometimes using an old nest from another bird as a base. photo by mnchilemom

Mourning doves create a rather flimsy platform of twigs, sometimes using an old nest from another bird as a base. photo by mnchilemom

The American goldfinch creates a cup shaped structure built of woven plant fibers including bark strips, all bound together using spider webs, caterpillar silk, and other woven fibers.

The American goldfinch creates a cup shaped structure built of woven plant fibers including bark strips, all bound together using spider webs, caterpillar silk, and other woven fibers. The goldfinch will always build it’s nest above a fork in a tree branch.

You can find a bird nest yourself by going out and following a bird carrying food or nesting materials, just remember not to get too close. Bring a pair of binoculars and look from a distance or wait until the nest has been abandoned to get a closer look. If you disturb the nest the baby birds might try to fly away before they are ready!