SAVING BIRDS: “Birds hitting windows is one of the leading causes of bird deaths in the United States,” according to the American Bird Conservancy.

“It is estimated that up to 988 million birds are killed each year in the United States when they hit windows, making this threat one of the most costly to bird populations,” the organization’s website stated.

We don’t know how they came up with that estimate, but we can’t tell you how often we’ve been interrupted by the sounds of a violent thump on the window — a sound we’ve come to recognize as the Thump of Death for unfortunate birds who never learned about windows.

The conservancy has found a list items that work well to keep birds from diving head-first into your squeaky-clean windows.

• ABC BirdTape is translucent tape that “allows light in, but partially obscures views.”

• Acopian BirdSavers, aka “Zen Curtains” are paracords that are hung vertically along the height of the window. Birdsavers.com recommends hangin the cords 4 ¼ inches apart.

• White CollidEscape is a “one-way” film that covers the entire window, looking white from the outside while allowing people inside to look out.

• Feather Friendly adhesive dots can be placed on windows.

• Solyx bird-safety film, a film which puts either vertical or horizontal lines across the window, makes it visible to birds.

These above items are all things to attach to windows, but here are also special types of glass you can install in buildings.

Other suggestions from the conservancy for living a “bird-friendly life” or avoiding use of pesticides, planting trees and native plants and drinking bird-friendly coffee by looking for the Smithsonian Migratory Bird Center’s Bird Friendly on coffee products.

Another big suggestion is keeping cats indoors.

As the American Bird Conservancy so-colorfully stated in a recent press release, “Invasive mammalian predators are killing endangered species around the world at much higher rates than previously known and are ‘arguably the most damaging group of alien animal species for global biodiversity,’ according to a recent study published in the Proceedings of the National Academy of Sciences. The findings are the latest evidence that cats and other invasive species pose a major threat to birds and other wildlife worldwide.”

The conservancy cites the results of the study, which determined that cats are to blame, at least in part, for the extinction of up to 63 species, 40 of them bird species.