What aquatic animals do birds hunt

Cats and birds

Although cats primarily eat special pet foods or home foods, they prey on small mammals, birds, reptiles, and other small animals outdoors.

Cat lovers regularly argue with people who assume that domestic cats cause damage to our nature. The following considerations should help to objectify the discussion:

The keeping of cats started to a notable extent in Central Europe around the 12th century. For centuries it served almost exclusively to combat rats and house mice, which had been introduced with the expansion of trade routes in the Middle Ages. It was only with the industrial revolution in the 18th and 19th centuries that cats increasingly received the status of pets in the modern sense. Based on representative surveys of the population, there were almost 1.4 million domestic cats in Switzerland in 2008. Of these, around 1 million animals are likely to have run outside and thus had the opportunity to hunt outside. The domestic cat does not belong to the native fauna and still shows essential characteristics of its wild ancestral form, the North African wildcat or falcon:

  • It roams through larger areas when hunting.
  • Although cats primarily eat special pet foods or home foods, they prey on small mammals, birds, reptiles, and other small animals outdoors.
  • Not all prey are eaten. Hunting is not only used to acquire food, but also to practice hunting.
  • Cats often prey on young animals because they are particularly easy to catch.

Can cats endanger bird populations?

An average of 50 to 60 cats per square kilometer live in the lowlands of Switzerland. According to projections, there are as many as 430 animals per square kilometer in the Zurich agglomeration. This means that cats are many times more common than all other predators combined.

Like all predators, cats avoid high hunting efforts, i.e. they primarily hunt animal species that are numerous and easy to catch. If the prey find enough food, hiding places and sheltered places for reproduction in their habitat and the other environmental conditions, e.g. the climate, are right, they themselves can cope with considerable losses from predators. But when their populations are already depleted, cats can lead to the extinction of local populations.

Mice are the main prey of cats; shrews also often play an important role. Frogs, newts, lizards and blindworms are badly affected in cleared, hideaway landscapes. Among the birds there are mainly common species such as blackbirds, robins, tits, finches and sparrows. Birds of endangered species, on the other hand, are seldom captured.

Determining the significance of the influence of cats on the populations of native small mammals, small birds, reptiles and amphibians is methodologically very complex. Accordingly, there are hardly any studies available. Because there are a lot of house cats around, especially in populated areas, and because they can be very efficient when hunting, we should consider suitable precautionary measures.

What to do?

Implementing the following recommendations can help reduce wildlife and bird losses by cats:

  • Only get a cat if you have the time and space.
  • Make it more difficult for cats to get to nesting places for birds as well as to amphibian and reptile sites: A sheet metal or plastic sleeve attached to the base of individual trees at a suitable height prevents cats from climbing up the tree. A cattle guard's wire stretched 20 cm above the ground can keep cats away from sensitive areas (e.g. a dry stone wall with a population of lizards).
  • Hang nesting aids on side branches or on facades at a height of more than 1.5 m and out of the reach of cats. Use nesting boxes with steep and smooth roofs that a cat will not find support on.
  • Provide optimal small animal habitats with plenty of hiding places (piles of branches and stones, hollow boards, dry stone walls, etc.). A leaflet on natural garden design is available from the ornithological station and from the Swiss bird protection agency SVS / BirdLife Switzerland.
  • Elderly people in particular, but also small birds, do not hear ultrasonic waves above 20 kHz; However, cats apparently find them uncomfortable. Appropriate transmitters are commercially available and can help make home gardens less attractive to cats. However, there is a risk that they have a similar effect on other mammals and annoy local residents!
  • Establish a conversation with cat owners. Let them know about areas with endangered bird species and about amphibian and reptile sites.
  • If you have a bird bath or a bird feeder ready for winter feeding in your garden, place this in a safe place for cats, i.e. in a clear place so that the cats cannot sneak up on them. Bird feeders should hang freely from a branch or be mounted on a post. However, avoid repellants such as barbed wire or the like, which could injure cats and other animals.

Cat owners should also note the following points:

  • It is forbidden to abandon cats.
  • Have your cats neutered. Especially the males then stray less.
  • Let your cat be looked after by neighbors or acquaintances during your vacation or take them to an animal shelter for care.
  • Put an elastic collar with a bell around your cat. After a short time she will get used to it. Birds become more aware of the danger.
  • If you see young birds that have just flown out in your garden or strongly warning adult birds, do not let your cat outside for a few days if possible.


We thank Dr. Dennis C. Turner, Institute for Applied Ethology and Animal Psychology, and Privatdozent at the University of Zurich, for critically reading this text.

Imprint: Leaflets for bird protection practice

© Swiss Ornithological Institute & SVS / BirdLife Switzerland, Sempach & Zurich, 2014
Authors: M. Rudin & J. von Hirschheydt
Copying is encouraged, provided the source is acknowledged.