Birds hitting windows: why, what helps, and a stunned bird

A thud on the glass is one of the more upsetting things that can happen in a garden you are trying to make good for birds. Two different things get called a window strike. One is a bird flying into a window at speed. The other is a bird that keeps attacking a window, sometimes for days, which is a behaviour problem rather than an accident. They have different causes and different fixes.

This page uses the BTO’s window strikes page and the RSPB’s injured bird page, both opened on 14 November 2026. We did not open a page that sets out first aid for a concussed bird step by step, so that part is kept short and points to people who can help.

Why it happens

Glass reflects. To a bird, a window showing the sky or a hedge can look like more sky or more hedge, and some windows give a clear view straight through the house to the garden on the other side. Neither looks like a solid object.

The BTO also describes the repeated-attack version. Some birds become fixated on their reflection and treat it as a rival on their territory. Their words are that many birds that attack windows become seemingly obsessed with their reflection. Others visit windows for food, gleaning insects from spiders’ webs or pecking at window putty, which the BTO says happens mainly in autumn and winter.

What people try on the glass

The common thread in what the BTO suggests is to break up or remove the reflection, and to do it on the outside of the glass, where the reflection forms.

• Non-reflective material. The BTO suggests covering the outside of the window with a non-reflective material such as cling film or non-reflective cellophane.
• Stickers. The RSPB’s injured bird page says flying into windows is a common problem which can easily be solved with window stickers. We did not open a page that gives a spacing for stickers, so we do not give one. A single sticker in the middle of a large pane is unlikely to break up much of the reflection.
• Things that move. The BTO suggests objects that dangle and catch the light and wind, such as strips of foil or old CDs.
• Plants in the way. They also suggest blocking access to the window with plants and hanging baskets.
• A decoy reflection. For a bird attacking one window, the BTO suggests a mirror near that window to give it another reflection to focus on. If several windows are attacked in turn, they say target the first one in the sequence.
• Putty. If the problem is pecking at putty, they suggest synthetic putty, covering it with masking tape, or brushing the frame with a substance birds find distasteful.

Fixes that make you feel better from inside, such as an internal blind half closed, may not change what the bird sees from outside. The BTO’s advice is about the outer surface.

Feeders, water and the window

Where you put the feeder affects how birds move around the house. The RSPB’s current advice is not to use window feeders at all, because flat surfaces spread disease; that is a hygiene reason, not a collision one, but it does take one cause of birds crowding against the glass away. We did not open a page that gives a safe distance between a feeder and a window, so we do not invent one. The rest of the siting advice is in where to hang a feeder.

If birds are flying from a bird bath straight at a large pane, think about the flight line. Moving the bath, or putting plants between it and the glass, changes the route. Daily changes and cleaning still apply, as in water for garden birds.

If a bird hits the window

Some birds hit, sit stunned for a short time and then fly off. Others do not. The RSPB’s page is clear that they are not the right organisation to call about an individual bird: they say they do not have the expertise or facilities to rescue birds.

What they do say:

• Find help locally first. It is often in the animal’s best interest. They point to the RSPCA’s rescue directory and to helpwildlife.co.uk.
• Try a vet. They say all vets should provide emergency first aid treatment to wildlife free of charge.
• If there is no local help, contact the RSPCA in England and Wales on 0300 1234 999, the Scottish SPCA on 03000 999 999, or the USPCA in Northern Ireland on 028 3025 1000. Those are the numbers the RSPB page showed on 14 November 2026.

While you are getting advice, keep cats, dogs and children away from the bird. Do not try to give it food or water unless someone qualified tells you to. That is common sense rather than a quoted rule, and the rescue or vet you speak to may tell you something different for that bird.

If a bird dies

A single dead bird under a window may well be a collision. If you find several dead or sick birds in the garden, though, that is a different situation, with reporting and hygiene steps of its own. Both cases, including how GOV.UK says to handle and dispose of a dead wild bird, are set out in sick and dead garden birds.

The window that keeps getting attacked

A bird repeatedly attacking its reflection is not usually injured, but it is wasting energy at a time of year when it may need it. Start with the outside of that window: break up the reflection, hang something that moves, or put plants in front of it. If it moves on to the next window, the BTO’s tip is to work on the first window in the sequence.

Do window stickers work?

The RSPB’s injured bird page says the problem can easily be solved with window stickers. The BTO’s wider point is to reduce the reflection on the outside of the glass, which stickers, cling film and hanging strips all try to do.

Why does a robin keep attacking my window?

The BTO says some birds become fixated on their reflection and act territorially towards it. Break up the reflection on the outside of that window, or give the bird a mirror nearby to focus on instead.

Who do I call about a stunned bird?

The RSPB suggests local help first: a wildlife rescue or a vet, who they say should give emergency first aid to wildlife free of charge. If there is none, the RSPCA, Scottish SPCA or USPCA.