I started using tennis balls around the garden as a joke once. They lived in pots and under benches like lazy, fluorescent stones. Then the first frost came and I noticed a robin skidding on the paving, wings flashing and then a tiny, sharp landing that looked wrong. After that I stopped laughing. Tennis balls are not a miracle but they are a blunt and surprisingly effective intervention in the bleak, fiddly theatre of winter wildlife survival. This article is about where I put them and why, and why installing a few bobbing or wedged balls around nets and water is a low-effort way to reduce harm to birds and hedgehogs.
What this trick actually does
When people hear tennis balls in a garden they imagine dog toys. The reality in frost and ice is more geometric. A tennis ball adds texture where the ground becomes glass. It creates a visual landing cue for birds that misjudge dark, shiny surfaces. It floats and moves on a bird bath so water does not freeze solid across the surface. When wedged across a narrow gap under a gate it prevents a hedgehog from squeezing into a dangerous crevice. Put bluntly the ball changes the physics of tiny movements and the behavior of small animals.
Not a replacement for proper net care
I want to be clear about a non-negotiable: tennis balls are a supplement not an answer to net-related dangers. Wildlife harm around nets is mostly about entanglement and neglect. Netting left loose or draped over shrubs is a hazard. The Royal Society for the Protection of Birds states that netting must be properly installed and checked frequently to avoid trapped animals. Tennis balls will not stop a bird from becoming entangled in a poorly hung net. What they can do is reduce the number of risky landings and provide small escape patches where animals find purchase.
Scattering tennis balls in your garden can benefit birds and hedgehogs as it can provide them with a stable surface during icy and wintry weather. The bright colour of tennis balls gives birds a clear place to land and their fuzzy surface functions as a non slip surface that they can perch on.
Richard Barker. Commercial Director. LBS Horticulture.
How I place them around nets and water
There is an instinct to overthink. I used to think the balls needed to be in the right pattern like some domestic crop circle. They do not. There are a few practical placements that matter more than aesthetic alignment.
Near bird baths and shallow water
Drop one or two clean balls into shallow bird baths and troughs. The wind will nudge them and the constant micro movement prevents an even glass sheet of ice forming. That means a centimetre or two of liquid remains at the edge where a hedgehog or small bird can drink without climbing onto a hazardous surface. Do not use them in ponds with fish where they might introduce contaminants or come apart on the edge of a pump. Clean the balls occasionally and replace any that are crumbling.
Close to nets and traps
If you use garden netting for vegetables or to protect shrubs from birds, place bright tennis balls along the lower edge of the net or tie a few to the structure so birds see a solid, lively boundary. The point here is visibility. Birds often fly low to inspect a net and misjudge depth or tension. A dot of colour and texture changes perception. For hedgehogs wedge balls into narrow gaps that border concrete steps or fencing. The ball acts like a doorstop that prevents a small creature from pushing into a collapse zone where it could get stuck.
Stories and small data points
People who rescue hedgehogs and birds tell similar, small stories. A dog walker stopped me one morning and said the ball I had jammed under a shed gap had saved a hog that would otherwise have pushed through and landed on cold concrete. These are anecdotal and carry the smell of directness that formal studies often clean off. It does not make them irrelevant. Gardens are messy laboratories and the world of small wildlife is built from thousands of local experiments. The tennis ball trick survives because it is cheap and because it is visible and actionable.
When it fails
Sometimes the balls are useless. A gust will carry them into a puddle. Dogs and foxes will drag them away. Sloppy netting will still entangle birds no matter how many bright dots you tie on. The key is routine and complement. Check nets. Remove loose knots. Use balls where they give a genuine behavioral nudge and not where they are merely decoration.
Practical cautions and ethics
There is an ethical edge here that people often gloss over. Tennis balls made of synthetic rubber and felt will degrade. Small pieces can be ingested by wildlife. Do not use balls that are actively shredding. More responsible alternatives include older but intact balls or other bright floating objects that do not flake. Keep an eye on pets and do not put balls inside deep containers where they could cause animals to climb and fall. Nets themselves must be the primary responsibility. The charity advice is unanimous: nets must be tight or replaced by wildlife friendly alternatives if possible.
Why this advice annoys specialists yet still matters
Conservationists will roll their eyes at quick hacks. They are right to be stern when hacks serve as excuses to avoid structural fixes. Yet, in cold, urban gardens where people have little time and less money, small interventions change outcomes overnight. A hedgehog that finds a thin water margin under an iced bird bath may survive the next 24 hours. I accept the compromise. I also insist on honesty about what the balls do and do not do.
My non neutral position
I do not believe in technofix fetishising. I also do not believe in moral perfection. Use tennis balls but use them as part of a daily practice. Check nets. Educate neighbours. Lobby for wildlife friendly products at local garden centres. This is modest activism with an immediate payoff. It is not enough to save species but it is enough to save individual animals at the margins. I choose the small wins because they are achievable and visible and because they may open people to larger changes.
Final notes before you scatter anything
There is an invitation here. Look at your garden at dawn. See where birds land where hedgehogs sneak. Put the balls where the ground becomes dangerous. Replace and clean them. Watch. The best advice I can give is not cleverness but attention. Little repeated acts of care add together in a way that calls itself community. Sometimes saving a life starts with seeing a robin slip and then placing a faded tennis ball where it can find purchase.
Summary table
| Problem | Tennis Ball Action | What else to do |
|---|---|---|
| Frozen bird bath | Float one or two clean balls to keep a patch liquid | Use shallow dishes and check daily |
| Birds mislanding near nets | Tie or place balls to increase visibility and texture | Install nets tightly or use geotextile alternatives |
| Hedgehogs stuck under gates | Wedge balls to block hazardous gaps | Create safe hedgehog holes and check boundaries |
| Ball degradation risk | Replace balls that flake or crumble | Use intact old balls or alternate floating objects |
FAQ
Will tennis balls actually prevent birds from getting entangled in nets?
Tennis balls are primarily a visual and tactile aid. They can reduce risky landings and help birds identify boundaries but they are not a substitute for properly installed and monitored netting. The most effective prevention is correct net choice and daily checks. Think of balls as a behavioural nudge not a safety certificate.
Are there risks in using old tennis balls in the garden?
Yes. Balls that are breaking down can shed small pieces that could be swallowed or cause harm. Replace any balls that are brittle or flaking. Clean any ball before using in drinking water and avoid putting balls in deep ponds with fish unless you are confident they will not interfere with pumps or filters.
Can this trick help hedgehogs during hibernation?
The trick helps at the edges of hibernation when animals still move and drink. A floating ball can keep a tiny patch of water available during cold spells which can make a difference to dehydrated animals. It is not a cure for habitat loss or chronic threats but it is a low cost, immediate intervention that can reduce short term risk.
Should I tie balls to nets or just place them nearby?
Both approaches have value. Tying balls to nets increases visibility and makes them less likely to be blown away. Placed balls are useful for water and wedged roles. Where possible tie or secure the ball so it does not become litter or a choking risk for pets.
What alternatives work as well as tennis balls?
Other bright floating objects that do not degrade quickly can work. Sections of sealed plastic bottles are useful in some water features. Fabric tied visibly and safely to nets can provide the visual cue for birds. The key criteria are colour contrast durability and absence of sharp fragments.
How often should I check balls and nets in winter?
Daily checks are ideal. If that is impossible aim for every other day during extreme cold or after storms. Nets should be checked more frequently because entanglement incidents happen quickly. Making checks a short routine will catch many problems before they become tragedies.
