Colourful collar cover or bell: each one protects a different prey
Published by Planète Pets · managing editor: Clément Lacaille · how our guides are written
The colourful collar cover and the bell are sold for the same job, and often set against each other. A Swiss trial suggests they simply do not address the same prey. Our equipment guides are gathered in the cat accessories section.
Contents · 5 sections
Thirty-one cats, three two-week phases
Geiger, Kistler, Mattmann, Jenni, Hegglin and Bontadina published an open-access trial in private homes in Frontiers in Ecology and Evolution in 2022 (see the study). Each household went through roughly two-week phases in a randomised order: no collar, then colourful cover. Only twelve households went on to a third phase, cover plus bell. What is counted is prey brought home — not prey killed.
- Birds: 25 returned without the cover, 14 with it, a reduction of roughly 37%.
- The analysis is Bayesian: the authors report an 88% probability of reduction, which is not a p-value. And the uncertainty is wide — the 95% interval runs from −72% to +35%, so it includes zero: the benefit for birds is a signal, not a certainty.
- Small mammals: the cover alone changed nothing.
- With the bell added, small mammal catches fell by about 54% compared with no collar and 62% compared with the cover alone, this time with a probability of reduction above 99% — but across twelve households.
Why two devices rather than one
The proposed explanation rests on prey sensitivity: colour vision is better developed in birds, high-frequency hearing in mammals. A conspicuous visual signal therefore alerts mainly the former, a sound signal mainly the latter. That is a coherent hypothesis, not a measurement: none of these studies observed the prey's own reaction.
One split in the literature remains unresolved. British work on far more cats found no effect of the bell; here the combination works. But the Swiss trial has no "bell only" arm: what is measured is the effect of the pair, and the credit cannot be assigned to the bell on its own.
The limits, which are real
Sample sizes are small, and reductions published elsewhere range from about 37% to nearly 80%: take a range, not a single figure. Above all, the measure is what the cat brings back, which underestimates prey eaten on the spot — and some returned prey may already have been in poor shape, since four of the fifteen birds examined post mortem bore signs of an earlier collision. On acceptance, of 43 households enrolled, 17 dropped out, four of them because of a collar problem; among those who finished, about 70% of cats had adjusted within a few hours to a day.
In practice
- Only on a breakaway collar, which releases if the cat snags it — see our article on whether your cat should wear a collar.
- Stack the levers: these devices replace neither dawn and dusk curfews nor daily predatory play, whose effect was measured separately.
- Plan a trial period of a few days: individual tolerance decides everything.
Frequently asked questions
What if my cat will not tolerate the cover?
Some cats never settle to it, and there is no need to insist. The measure that removes predation entirely is contained outdoor access: see how to cat-proof a balcony, and all our guides on the cat hub.
An accessory from our shop for this use: Stainless-steel pin brush for cats (€18.90) · the whole shop
See it at Le Félin, a shop from the same family (zero commission): Coussin douillet pour chat (from €9.99)
This guide is part of Planète Pets’s Cats universe. Our advice is general in nature: for any health concern, your veterinarian remains the only reference.