Treacherous Glass: Bird Collisions with Windows

by Jan Thornhill

Ruby-crowned Kinglet (Dania Madera-Lerman)

It’s October and fall bird migration is ongoing. Though most warblers have already crossed our southern neighbour’s border, many other songbirds, as well as shorebirds, ducks, and raptors, are still moving south.

Migration is fraught with danger and hardship for birds. Many fly thousands of kilometers, following flight paths established by their ancestors millennia ago. But things have changed. Suddenly (at least in millennial terms) there is a new hardship: cities filled with glass-windowed buildings have been built smack in the middle of some of these flight paths. And these glass-windows are lethal, even to the healthiest bird.

A Ruffed Grouse victim

Migration season isn't the only time that birds are killed by glass—it happens in all seasons, and it happens everywhere. In the United States alone, it’s estimated that from 100 million to one billion birds die each year from window collisions. Put another way, that’s 1-10 birds per building per year. These are shocking numbers.

As a human, I have to say I’m quite fond of windows. They allow me to look outside, which keeps me from feeling imprisoned while I’m stuck at my computer inside. Nice for me, but not good for birds.

Birds, such as doves, that have powder down feathers sometimes leave behind
ghostly reminders of their collisions with glass. (Beth Woodrum, Wikicommons)

Though birds have amazing visual capabilities—they see more colours than we do and can process what they see faster—hard, transparent glass is not something they recognize as a barrier. What they do recognize are trees, water, dark spaces. If they see a tree reflected in a window, they assume they can navigate through its branches. A group of potted shrubs in a glassed-in atrium looks like the perfect place to perch and have a rest. The reflection of a fountain is a drink of fresh water. A dark space indicates a safe “fly through” zone. Birds don’t slow down when they see these things, so when they hit windows, they hit them hard. About half will die immediately, usually from brain hemorrhages. Others can have broken wings or beaks, concussions, or other injuries that make them easy victims for predators.

In some cities, gulls have learned to patrol high incident areas
to scavenge recent kills and injured birds. (Wikicommons)  

So What Can Be Done? And What Is Being Done?

Reflections can be blocked with physical barriers, such as netting or shades. Glass can be etched or otherwise marked to create recognizable “no-fly” zones. New panes have been developed that have external patterns that birds can see from the outside, but that are invisible from the inside. Here is great document put together by the Bird Conservancy of America that has lots of pictures of amazing architectural solutions for bird-safe buildings.

Double-whammy corner windows show foliage reflected in one window
as well as a clear view of trees and sky through a second window. 

Largely due to grassroots organizations such as Toronto’s FLAP and the American Bird Conservancy, businesses and government are beginning to respond. Researchers, basing their work on avian vision and behavior, have been coming up with novel solutions for building “bird-safe” structures and for modifying existing problem areas. Governments, including those of Toronto and New York State, are gradually coming on board, by putting in place legislation requiring new buildings to be bird friendly.

What You Can Do at Home:

Single decals like this DON'T work. They're only effective
if you cover the window with them.

• place bird-feeders and bird baths half a meter or less from windows
• move houseplants out of the sight line of birds
• hang string or ribbon vertically 4" apart in front of windows
• decorate windows with patterned window film (i.e. FeatherFriendly's DIY tape) 
• more solutions from FLAP

Children's Books About Bird Migration:

• Is This Panama: A Migration Story (Owlkids): Jan Thornhill & illustrator Soyeon Kim—my 2013 book's main character, Sammy, meets office tower windows (and other migrating characters!) on his epic first journey from the Arctic to his wintering grounds in Panama

• Moonbird: A Year on the Wind with the Great Survivor B95  (Farrar, Straus and Giroux):  Phillip M. Hoose—award-winning book about the "world's most celebrated shorebird" illustrated with photographs 

• The Long, Long Journey: The Godwit's Amazing Migration (Lerner): Sandra Markle & illustrator Mia Posada—follows a young godwit from hatching to first long-distance migration, with beautiful watercolour/collage illustrations

• How Do Birds Find Their Way (Let's-Read-and-Find-Out Science 2) Roma Gans & illustrator Paul Mirocha—facts about bird migration with well-labelled species and maps

“Potbelly Hill” gives birth to new theories of civilization

By Judy Wearing

Tall, flat stones arranged in circles stand straight, their limestone edges sharply sculpted. Some are six metres in height, and decorated with a menagerie of carvings: lions, gazelles, foxes, donkeys, bulls, reptiles, insects, and birds. The pillars are enclosed inside circular walls. There are four such enclosures, back to back, each surrounding up to eight pillars each. Sixteen more enclosures remain out of sight, under the earth. These 'rooms,' with their rings of standing stones, were buried at Gobekli Tepe (potbelly hill), a man-made mound 15 metres high, located in Southern Turkey. These awesome monuments were made without metal. They were sculpted with stone tools, and transported hundreds of feet from a quarry without beasts of burden or wheels. At the time they were built, writing had not yet been invented. Neither had pottery. Their discovery has changed the way archaeologists think about human civilization.

Gobekli Tepe rivals Stonehenge in its complexity, but predates it by some six thousand years, hailing to 9600 - 8800 BC. It is older than the pyramids and the ancient cities of Ur and Catalhӧyuk. It is the oldest known building project on Earth. But it is not its age per se, its engineering, or even its artistry that make Gobekli Tepe so special. It is that the people who created and used it were nomadic hunter-gatherers living before the invention of agriculture. There is no local source of water, no traces of housing, cemeteries, domesticated animals or plants. The people who built this 'temple' did not live here, nor anywhere else permanently.

The existence of Gobekli Tepe turns the common understanding of the development of human civilization on its head. The old way of thinking has humans in Mesopotamia discovering that wild grains can be saved and planted, and wild animals captured and contained. This ‘Neolithic revolution’ encouraged people to settle in one place, growing and keeping food instead of hunting and gathering it. Then, as a consequence of the new stability, came increased food supply, growth of community, cooperation, division of labour, extra time to devote to art and architecture, religion, organized cemeteries, public buildings, etc. Gobekli Tepe, however, was built by a number of people over a significant amount of time, organized, cooperating, and practicing a common  religion -- all without the existence of stable, permanent settlements.

Besides demonstrating that long-held beliefs can be wrong, and that early human societies were more complex than previously thought, Gobekli Tepe is a spectacular site in its own right. What people were doing here is still a mystery, and the lack of writing means there is no voice from the past to tell us what these structures meant to their culture. There are some intriguing clues, however. For one, some of the T-shaped stones have belts and arms carved on them, suggesting they are stylized representations of people. For another, what look like benches are built into the walls – for visitors to rest awhile, dead or alive, in the company of the stone statues.

Some believe that Gobekli Tepe’s stone circles were sanctuaries to link the world of the living with the world of the dead. Today, they still function as a link to the world of the dead, the only connection we have to the culture that lived and died in that part of Turkey more than 11,000 years ago. The stones still tell stories of their builders, whispering secrets of our distant relatives.

Tales in time: Criccieth Castle

By Marie Powell (Photos by L. L. Melton)

I love castle hopping, and Wales is one of the best places to explore ruins from bygone days. With some 400 castles in about 20,000 square kilometres (8,000 square miles), there's a lot to explore.

Last year I had the chance to see Criccieth Castle, located at the top of a rocky hill overlooking Cardigan Bay, North Wales. According to the Cadw's Criccieth Castle guidebook, the earliest records of the castle date from the 1230s, when Llywelyn ab Iorwerth (Llywelyn the Great) made it a main seat of power in North Wales.

He built the inner ward of the castle, including the twin towers, using a mix of angular stones from the rock around the castle, glacial boulders, with grey mortar made from beach gravel. The D-shaped towers are typical of Welsh native castles, but these twin gatehouses may have also been influenced by castles of the Marcher lords at Cheshire and Montgomery.

The various princes and kings who owned and controlled Criccieth had a hand in adding to its architecture. Although determining the date of a castle ruin might seem straightforward, there is a controversy over who built what part of Criccieth. Experts turn to structural evidence in the ruins to develop their theories and time estimates.

For example, Llywelyn ap Gruffudd (Llywelyn the Last) added an outer ward to the castle. The mortar used in his time is more gravelly, with stones and boulders brought to the site (rather than quarried from the castle rock) along with blue-grey slate. Experts believe the square holes about eight feet from the top mark the height of the towers during the time of the Welsh princes.

Arrow slits that can be seen at the ground level of the towers, as well as at strategic positions throughout the castle, offered a protected spot for archers guarding the castle from attack. Criccieth had several other buildings and towers as well, including one thought to have housed a trebuchet (a machine to throw stones) or a catapult for warding off enemy attacks.

Criccieth fell to Kind Edward I of England in March 1283, and was later held by Edward II (1307-1327) as well. They built up the top of the towers to the height we see today. The square holes held horizontal beams for a fighting platform (or "hourd") projecting from the wall. The English also used castle rock again, but the mortar from this period contains more shells.

Edward II spent over £250 on repairs and refurbishing, according to the guidebook. The castle was finally destroyed in about 1404, during the time of Owain Glyndwr, and was never rebuilt.

A small museum and gift shop at Criccieth tells more of the history and architecture of the castle, with colourful floor plans such as this one.

Another useful resource is the Castles of Wales website, which includes a discussion of the history, geography, architecture, and archaeology of this and other Welsh castles. As well as the guidebook, Welsh Castles by Adrian Pettifer also offers discussion of Criccieth and other castles by area.

Marie Powell is the author of seven books for children, including Dragonflies are Amazing (Scholastic Canada) and a six-book Word Families series (Amicus Publishing). Her second six-book series is expected this fall.

Solar Powered Building at Concordia University

Text and photo by Marie Powell

Buildings use a lot of energy. We only have to see a city at night to realize that. Harnessing the sun to power a skyscraper sounds like the stuff of science fiction - but in Montreal, it's becoming science fact.

Concordia University has been a leading researcher into renewable energy sources for at least 25 years. In December, 2008, it became the site of a unique 17-story building that gets its light and heat from solar power. It's called the John Molson School of Business (left), and it's the first of its kind. I saw this building first-hand in June, at a conference on the Concordia campus in downtown Montreal.

At the very top you can see the dark solar panels across the width of the building, called the solar facade. This facade provides provides both heat and electricity, and is known as a Photovoltaic/Thermal (PV/T) application.

On the Concordia website, there's a useful document explaining how the energy system works, complete with flow charts and close-up pictures of the panels (SBRN Demonstration Solar Project). According to this report, the solar panels take fresh air from outside and heat it as much as 20 degrees on sunny winter days, maximizing energy efficiency even in cold weather. That's important because, overall, buildings use about 30 percent of the secondary energy produced in Canada, such as natural gas and oil, and about half of its electricity. I wonder how much energy could be saved, if all of Canada's buildings got light and heat from solar power.

Many partners collaborated on this project, including Concordia's Building, Civil and Environmental Engineering Department, Natural Resources Canada (NRCan), and Conserval Engineering, a company that won a major Renewable Energy award for the PV/Thermal Solar Wall (this link shows an online video of the award.)

Here are some resources to check for more information:

"Concordia to head research into cold-climate solar power technologies" (Montreal Gazette, June 8 2006)

"Innovative Solar Technology Showcased in State-of-the-art Building," by Laura Nichol (NRCan website, March 2009)

"Le Quartier Concordia - John Molson School of Business," by Christopher Henry (Architecture Daily, July 2011)

SBRN Demonstration Solar Project (pdf document), Concordia website (www.bcee.concordia.ca)

Marie Powell is the author of Dragonflies are Amazing! (Scholastic Canada).