Ever found a beautiful bird dead outside your home? Chances are it smashed into your window and never recovered. For every dead bird you find, just imagine how many were snatched up by a cat or pulled into the brush by some other critter. Worldwide, window collisions kill close to a billion(!) birds every year. Now is as good as ever to make your home bird safe. The DIY experts at Stack Exchange tell you how.

Image: Sean Gallagher.

Question

Over the last three days, I have probably had over a dozen birds try to fly through my sunroom, only to be stopped by the 1.82 x 1.32m sliding windows. Three of the birds have died.

What can I do so that the birds realise there is something there, thereby preventing them from flying into the window?

— Dan McClain (originally asked here)

The NYC Audubon Chimes In

After habitat loss, the greatest threat to wild birds may be glass windows.

NYC Audubon started Project Safe Flight in 1997 to address the issue in New York City. Daniel Klem, an ornithologist at Muhlenberg College, estimates that close to a billion birds are killed every year by flying into glass. A study he conducted, with NYC Audubon, found 1.3 birds killed per hectare per year in an urban setting, which works out to over 90,000 birds per year in New York alone.

All bird species are vulnerable, although migratory songbirds are the main victims. Most are killed instantly, but others succumb when they are stunned and fall prey to gulls, rats, or other predators.

We have rescued over 1200 birds, persuaded buildings to retrofit their more dangerous windows and published Bird-Safe Building Guidelines to help architects and designers develop solutions in new buildings.

Private homes as well as skyscrapers endanger birds. Most home owners have heard the unpleasant thump that means a bird has hit a window; many have also found bird carcasses near their windows. Birds do not see the glass as a solid barrier; they see reflections of trees or sky or a fly-through to open space beyond. This should come as no surprise, since even people occasionally walk into glass doors. For a person it is merely embarrassing, for a bird it is often fatal.

Homeowners can reduce the collisions and save bird lives in a number of ways:

- Bird feeders should be placed within a metre of a window, so that birds visiting the feeder cannot get up enough flight speed to hurt themselves.

- Installing a pattern on a window where birds are known to hit can be uncomplicated and inexpensive. Patterns with negative space no greater than the size of a hand, are most effective.

- Decals of hawks or other raptors are not particularly successful, unless the decals are spaced very closely — and then it doesn’t really matter if they are of birds of prey or an abstract design.

Some suggestions for temporary or seasonal fixes:

– Place vertical tape strips at a maximum of 10cm apart or horizontal strips a maximum of 5cm apart. ABC BirdTape, is long-lasting and more aesthetically pleasing than masking tape or electrical tape, though all are effective. Be sure to place the tape on the outside of the window for maximum effectiveness.

- Soap windows, or use window paints or tempera paints to obscure most of window.

- Purchase or make your own window gel clings. Be sure to space them no more than 10cm inches apart horizontally and 5cm inches apart vertically.

- Draw blinds and move indoor plants away from windows. This will not work if there are strong reflections of the landscape in the window.

For more permanent fixes, ones that keep birds from striking glass or lessen reflectivity and transparency, we suggest:

Install a frosted or opaque window film. Collidescape is a film that looks opaque from the outside, but allows views out. Films are most effective when applied to the outside of the window. Most films are not guaranteed when placed on the outside surface, but many are reasonably long-lasting on these surfaces.

- Install awnings, lattice work, or shades in front of windows.

- Install mesh window screens.

- Install unobtrusive netting in front of window. A company called Bird B Gone has designed several types for glass windows and facades.

The ultimate solution would be a glass that is visible to birds but not humans. A product called Ornilux Mikado, manufactured in Germany by Arnold Glas, incorporates an ultraviolet spidery crisscross pattern within the glass visible to birds but nearly invisible to us.

Watching birds and nature from inside your home should be a pleasure. Bird fatalities are an unintended consequence of home design. But with some creativity and imagination, you should be able to see your birds and keep them safe.

— Answered by Glenn Phillips NYC Audubon

Answer: More Options

There are two reasons birds fly into Windows, either they can’t see the glass or they see a reflection in the glass. The only real solution, is to make the window more visible or less reflective.

Unfortunately, making the window more visible to birds also makes it more visible to humans. So the solution may not be exactly… um… fashionable.

One solution: put decals, tape, paint, marker, or some other type of markings on the windows. You could also try hanging wind chimes, or other decorative items inside/outside the window.

Another solution that seems to be successful, is to hang fine mesh over the windows. The theory here is that the mesh will reduce the reflection on the windows, so birds will be less likely to think they are flying into whatever is reflected in the window.

The good news is, you may only need to do this during migratory seasons. So you could pick up a window paint marker (~$US5.00), and draw lines, squiggles, or patterns on the windows during migratory seasons.

You could try making up some detachable screens for the exterior of the windows and put them up during the migration season. This might be a less noticeable solution.

— Answered by Tester101

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To work in the file room of the downtown criminal courts building is to be a librarian of evils. Its shelves hold the official records of rapes, murders, robberies and thousands of other offenses prosecuted in the courthouse and the clerks there know the ugliness of society by name and case number.

It is perhaps not surprising then that on his lunch hour, an employee named Marcos Saldana was drawn to a scene of natural beauty. It was a ravens’ nest on the ledge of a building across Temple Street and Saldana watched each spring as the same pair of birds rebuilt the nest, hatched their chicks and taught them to fly.

“Birds are beautiful,” Saldana said, standing at his usual vantage point, a window in the L.A. courthouse’s 13th floor snack bar. “They can fly away and go wherever they want, whereas we are stuck to the ground.”

This April, Saldana’s fifth watching the ravens, the view changed in a way that made him fear the birds and their chicks were about to join a group with which he was well acquainted: victims of violence.

Saldana raised an the alarm in keeping with his soft-spoken, unassuming manner. He whispered his worries to a file room patron, a reporter, and offered photos — with an apology for their quality — of purplish black parents dropping food into the gaping mouths of a blurry brood.

In doing so, Saldana appears to have accomplished on his noontime repast what two government-paid biologists did not. He guaranteed the safety of the birds and might even have prevented a federal crime.

The nest in question is on a window sill of the vacant Hall of Justice, the historic former jail and courthouse. Shuttered after the 1994 Northridge earthquake, the Beaux Arts pile is undergoing a $231-million renovation into offices for the Los Angeles County Sheriff’s Department and district attorney. When the project received funding last summer, Saldana wondered vaguely how it would affect the ravens, but his concerns grew this spring when workers built a protective canopy over the sidewalk beneath the nest and there were courthouse rumors about a giant power wash planned for the granite exterior.

“I wanted the babies to have time to get out,” Saldana said.

Ravens don’t normally get that kind of human attention. They are the geraniums of the birder world, their prevalence a bore to serious connoisseurs. They thrive throughout the country, often on a diet of other birds and garbage, and even the name of their species — common raven — carries an implicit yawn. But as Saldana, who spends weekends watching rarer birds, was quick to note, ravens can be captivating. They fly in an elegant progression of swoops and dives. They usually mate for life and share child-rearing duties. And they are intelligent. The Audubon Society’s field guide puts their reasoning ability at “comparable to that of a dog.”

Given their smarts, it was hard not so see some ironic wink in their choice of home. For centuries, ravens have been a near universal symbol of death, and Saldana’s birds were roosting on a building whose cells housed Sirhan Sirhan, Charles Manson and Richard Ramirez and whose basement coroner’s office was the site of the autopsies of Marilyn Monroe and Robert F. Kennedy.

While their presence riveted Saldana, no one at the construction site seemed to take notice, an issue because the ravens are protected by federal law. A 94-year-old statute, the Migratory Bird Treaty Act, makes harming native birds or their nests a crime punishable by up to six months in prison and a fine of $15,000.

“It seems kind of ridiculous when it’s a common species, but when birds have an active nest, it’s against the law to destroy it,” said Kimball Garrett, the ornithology collections manager at the Los Angeles County Natural History Museum.

Told of the Hall of Justice’s raven residents, a manager at the county Department of Public Works expressed shock.

“We just had a biologist out there, and they didn’t find anything,” said assistant deputy director Jim Kearns.

To ensure compliance with the law, the county has a three-year, $40,000 contract with an engineering firm whose biologists are to survey the site every 10 days during nesting season.

“No active bird nests or nesting birds were observed on site,” a supervisor from Burns & McDonnell Engineering wrote in a report summarizing the results of four site visits since late February by a pair of biologists.

During an April 18 visit, he wrote, the biologists saw a single raven “circling and perching” but noted that it had no mate and was not nesting.

“It would be hard for a biologist to miss that,” said veteran bird watcher Ron Cyger, the former president of the Pasadena Audubon Society. “A raven nest is pretty large. You couldn’t miss it really.”

After The Times’ query, a biologist, a county project manager and the contractor went to the site and located the nest. The biologist initially identified the birds as American crows, a close cousin of the raven also protected by federal law. But informed by a reporter that Garrett, one of the country’s most eminent bird experts, had said the birds were ravens, a county spokesman said the biologist would revisit the identification. A few days later, he said the biologist had concluded the birds were indeed ravens.

No work on the exterior of the building is planned for several months, but the project manager said in a report related through a county spokesman that the area around the nest will be cordoned off “to assure no disturbance for the next four weeks or until we can confirm the hatchlings have fledged.”

After the chicks are gone, the nest will be removed “to alleviate future use,” according to the report.

Saldana is betting the birds come back anyhow.

“I would like to think I’ve been able to keep them safe,” he said.

harriet.ryan@latimes.com