Why Birds Peck Windows in Fall – the Real Reasons Revealed by Experts

Folk have long discussed why backyard birds peck windows in fall, and once Google got involved, plenty more possible causes were added to the pile. Now research and observations from bird experts have revealed the real reasons behind this bizarre behaviour, and you may be surprised to learn what they are.

Some of the most common speculations about why birds tap windows include attempting to get your attention when it's time to refill feeders, impending bad news, small songbirds wanting to come into the warm, and a message from a passed loved one. Avian experts, however, have put forward reasons based on cold, hard data, and they provide a fascinating insight into fall bird behaviour.

Whether you find the tap-tap-tapping of your beneficial garden friends endearing or highly annoying, once you understand the real reasons avian experts say are behind window pecking, you can better support your garden birds in fall. Understanding the likely causes will also help you decide if should take action to stop the window tapping to save birds from harm, and save your sanity, too.

Why Birds Peck Windows in Fall

1. Hunting for Insects

As temperatures decrease in fall, insects become more scarce, many birds are forced to forage for food in new areas. Because glass retains heat from the sun as well as windows allowing some of a home’s heat to escape, any tiny gaps in frames become welcoming nooks for insects to enter diapause (similar to hibernation) – and consequently, one of those spots hungry birds may favor. You might think modern windows don’t offer much space for critters to hole up in, but those drainage weep holes and sliding tracks provide plenty of opportunities. Spiders also use window corners to spin insect-catching webs and lay eggs, offering further protein-rich food to the bird buffet.

According to the British Trust for Ornithology (BTO), there’s a rise in birds pecking at windows for food in fall and winter, and in particular by the tit family which includes chickadees and titmice. The organisation also cites that birds may pick at traditional window putty as it’s made with fish or linseed oil, both a valuable source of energy in colder months.

2. Confusion Caused By a Low Sun Angle

Research carried out by the Cornell Lab of Ornithology found that the lower angle of sunlight hitting windows in fall significantly increases how reflective the glass is. Aside from birds having no concept of what a window is, our feathered friends see differently to us. Most birds have eyes on the sides of their heads to give them almost-360° vision, and while that’s highly useful for spotting potential predators, it means their forward vision isn’t as good as ours. So, reflections in windows are easily interpreted as extra habitat and when birds encounter the glass – which in fall, especially, can appear to them as an invisible barrier – they may peck at it repeatedly to investigate.

3. Young Birds Learning About Their Environment

Fall is when juvenile birds disperse, and these inexperienced youngsters have a lot to learn about the world around them, and much spatial awareness still to develop. Data published by the American Bird Conservancy and the US Fish & Wildlife Service shows a strong rise in what they term ‘glass interactions’ in fall. While many of these will be window collisions caused by mirror-like glass and navigational error, some will be window pecking led by curiosity as birds investigate their surroundings.

4. Resident Birds Being Territorial

While territorial behaviour among most of our feathered friends peaks in spring, many resident birds claim their territory in fall, according to the National Audubon Society. Northern cardinals, non-migrating American robins, northern mockingbirds, towhees and bluebirds are all highly territorial through fall into winter. And there's a very good reason for this, because as summer broods disperse, thousands of juvenile birds search a new territory. In the face of this competition, existing populations fiercely defend their established territories – especially if it contains a valuable food source such as a garden shrub hung with berries birds love through winter!

With windows becoming mirror-like in the low fall sun, dominant birds can attack their own reflection, mistaking it for a competitor. So this is a common reason why birds tap windows in fall as well as spring.

How To Stop Birds Pecking at a Window

Whether you have a towhee aggressively pecking at your patio doors or a chickadee tap-tapping your bedroom window at all hours, now you understand what’s behind this behaviour, you can do something about it. Gentle pecking for food harms neither bird nor human, so it’s safe to ignore this low-level behaviour. But more insistent pecking at a window, fighting imagined aggressors or attempting to break through an invisible barrier is not just highly annoying to us but harmful to birds, damaging beaks and wasting valuable energy.

Taking action to stop birds pecking windows involves making glass more visible, or keeping birds away from it in the first place. That means these solutions will also reduce the risk of feathered friends flying into windows and injuring themselves. By working out the likely reason behind a bird tapping on your window, you can choose the method that will be most effective.

1. Move Houseplants Off Windowsills

Your first step to stop birds tapping windows is to move any houseplants away from windows that are being targeted. To a young bird, a windowsill full of greenery can look like inviting habitat or contribute to the illusion that this could be a continuation of their flightpath.

2. Try a Strip of Reflective Tape

A quick and cheap solution if the targeted window opens is to shut a length of double-sided reflective bird scare tape like this from Amazon in it. When the tape blows in the wind, its holographic surface casts erratic patterns of ultraviolet light which most birds perceive as a threat. For resident birds in search of tasty insects, this may be enough for them to deem that window an unsafe zone.

3. Stencil Glass With Oil-Based Marker Pens

While the go-to for making windows more visible to birds and preventing collisions is decals, they're only effective if the gaps between them are narrow enough. A few decals dotted about on a large window are next to useless as birds will likely perceive the areas between them as possible flightpaths, just as they do the gaps between branches in woodland.

A far simpler, more effective and still-stylish alternative is to create a grid of dots around 2 inches apart across the entire window. Use a white oil-based permanent marker like a Sharpie Medium Point Paint Marker, available from Amazon, and for a professional result, use a stencil template. You could make your own by punching holes in cardboard or save yourself the trouble with an Avi-Dot Bird Saver Window Stencil from Etsy.

4. Use Collision Tape

Another effective way to help birds see house windows as a barrier is to stick on clear collision tape like CollidEscape, available from Amazon. To be effective against bird strikes, and therefore cut down on curious birds pecking at what they perceive as an invisible wall, you’ll need to position the tape in vertical or horizontal stripes with the edges no more than 2 inches apart. If you have feathered friends that often peck at a particular part of a window, this is a useful method as you can reduce the gap between strips here.

5. Create a Temporary Cardboard Barrier

If a particular bird still persists in pecking at a window, creating a temporary cardboard barrier can help break the habit.

6. Use a Permanent Reflective Deterrent

If you have a problem with a particularly territorial or bigger bird such as a woodpecker or seagull, a final resort is to fix a permanent deterrent near to the targeted window. Wind-powered metal spinners throw out unpredictable flashes of light, visually confusing birds to create an area they perceive as unsafe. Windmill spinners like these Stainless Steel Bird Deterrent Devices by Ebern Designs on Wayfair mean you don’t have to compromise on garden style.

Backyard birds need our support more than ever once fall turns to winter, whether that's preventing a bird bath freezing over to preserve their water supply, saving up kitchen scraps to feed feathered friends, or making sure smaller songbirds get a fair share of food. Now you understand why birds tap on windows in fall, you can decide whether or not to ignore the behaviour or take action for your and the bird's benefit.