Window Strike
A window strike is when a bird flies into glass it cannot see, often causing head trauma, internal bleeding or eye injuries that need veterinary or wildlife rehab care.
Also known as Bird Window Collision, Window Collision, Bird Strike on Glass, Glass Collision in Birds
Glass is invisible to birds. They see the sky, trees or garden reflected in a pane, or the open space visible through it, and fly towards what looks like a clear route or a place to land. The impact happens at full flight speed, which is why a window strike, also called a collision with glass, causes so much damage in a fraction of a second. The scale is bigger than most people realise: German bird protection authorities and NABU estimate that roughly 100 million birds a year die in Germany after hitting glass, and the American Bird Conservancy puts the figure in the United States somewhere between 365 million and one billion. Most of these accidents happen at ordinary houses, conservatories and low buildings rather than at skyscrapers.
The typical injuries are ones you cannot see from a distance. Concussion and bleeding inside the skull are common, along with bruised or bleeding internal organs, scratches and ulcers on the surface of the eye, broken wing or shoulder bones, beak damage, and pelvic injuries in birds that threw their legs forward at the last moment. This matters because a bird that shakes itself off and flies into a bush is not automatically fine. Swelling in the brain and internal bleeding can build up over hours, and a dazed bird is also easy prey for cats. Rehabilitators see plenty of collision birds that looked bright and lively on arrival and turned out to have serious injuries.
Companion birds are affected too. A parrot or budgie flying loose in a room can hit a window or a mirror just as hard, and the same head, eye and wing injuries apply.
What to do and when to get help
If you find a bird after a collision, pick it up gently with gloved hands or a cloth and put it in a ventilated cardboard box with a lid, somewhere dark, quiet, warm and safe from pets. Do not offer food or water, and handle it as little as possible, since being held is frightening rather than comforting for a wild bird. Some birds recover within an hour or two and can be released outside where they were found. Contact a vet or a wildlife rehabilitation centre if:
- the bird cannot stand, is unsteady, or tilts its head
- there is bleeding, an obvious wound, or a wing hanging oddly
- one eye looks cloudy, closed or damaged
- breathing is laboured or noisy
- it has not recovered enough to fly after a couple of hours
Rules on handling and keeping wild birds differ by country, so a local wildlife centre or vet practice is the right first call, and many take these cases routinely.
Prevention works, and it is cheap. Markings belong on the outside of the glass, spaced closely enough that no bird sees a gap wide enough to fly through. Dots, stripes and patterned films all do the job. A single sticker in the middle of the pane, including the classic bird of prey silhouette, does not.
This entry is general information. A bird that has hit a window and is not clearly back to normal needs an examination.