A difficult relationship

Domestic cats rank at the top of the popularity scale as pets. More than 14 million live in Germany. Cat lovers can do a lot to keep the number of garden birds killed within limits. The NABU has some tips ready.

Domestic cat – Photo: Helge May

Domestic cats rank at the top of the popularity scale as pets. More than 14 million live in Germany (as of 2019) and by no means all are under the care of humans. According to estimation nearly two million stray ownerless around.

But also the other house cats do not stay only in apartments and houses, but often roam around outdoors. Like their feral counterparts, they stalk and prey on birds, but also other wildlife such as larger insects, amphibians, reptiles and small mammals.

The number of cats is particularly high in residential areas. Since there is usually also a high density of songbirds, especially in the gardens, the table is always richly set for these predators. Their hunting of blackbirds, finches, robins, titmice and other garden birds therefore regularly leads to disagreements between cat owners and bird lovers.

The cat does not let the mouse.

Our domestic cat is descended from the Egyptian hawk cat, a wild cat. Despite thousands of years of domestication, it has remained a predator and has retained many of the characteristics of its wild ancestral form. So cats do not leave the mousing, even if they are well supplied with food and actually would not need to go in search of food. Following their hunting instinct, they roam larger territories and catch mainly house and field mice.

But also songbirds belong to the prey spectrum. As the institute for domestic animal science of the University of Kiel determined, they make up nevertheless well twenty per cent. But not all victims are eaten. The stalking and grabbing of prey serves not only the acquisition of food but also the acting out of the play instinct and, in the case of young cats, the practicing of hunting behavior.

Especially common species are preyed upon

Since the birds in the settlement area are exposed to a strong enemy pressure, they are under stress. In addition to corvids, griffins, owls and mammals such as squirrels and martens, domestic cats play a not insignificant role in this process. Like other prey predators, they also avoid an energy-consuming hunting effort. Therefore, they usually prey only on common species such as blackbirds and titmice. Young birds as well as birds weakened by age or illness are particularly easy prey.

However, the decisive factor for the stability of bird populations is not the number of their enemies, but the quality of their habitat. Where there is adequate food, nesting and hiding, birds can successfully reproduce and usually cope well with losses to predators, including cats.

Danger for ground nesting birds

Since our feathered neighbors in the cultural landscape are exposed to a variety of damaging influences, the high density of cats in urban and rural fringe areas can contribute decisively to the extinction of local populations of endangered bird species such as the ground-nesting skylark.

As a cat owner, you are responsible for your pet, even if it roams unattended in the garden during the day or night. Cat owners should also take the wild birds into their hearts, because love of animals should be indivisible.

Thomas Schmidt

Tips for cat and garden owners

Cat lovers can do a lot to keep the number of garden birds killed in check

Only get a cat if you have enough time and space to do so. Play with it more often. Also in such a way it can live out its hunt and play instinct.
The abandonment of cats is prohibited by animal welfare law. Masterless cats have to hunt in order to survive. They eat mainly preyed wild animals and therefore also more often birds.
Provide reliable care for your cat during longer absences. If this is not possible, you can also temporarily place the animal in a shelter or boarding kennel.
Have both male and female cats neutered. They become more domestic and roam around less. At the same time you avoid replenishment for feral cat populations and you don’t have to worry about the whereabouts of the offspring either.
Think especially in spring about the birds outside. Then many a young bird falls victim to ownerless and stray house cats. Therefore, especially from mid-May to mid-July, it is best not to let your cat out of the house in the morning hours, or at least not to let it outdoors unattended.
A collar with a small bell makes the birds aware of the cat, but is of no use to the still helpless bird offspring. In addition, the ringing is an ordeal for the sensitive cat ears.

Design your garden close to nature. Perennials, shrubs and trees provide many hiding places for birds. On a short cut lawn blackbird, thrush, finch and starling stand as on the presentation plate and invite cats virtually to make prey. In an eco-garden, other wild animals such as newts, frogs, lizards or slow worms also find protection from hunting cats.
To keep cats away from nests in trees, you can put sheet metal or plastic defensive collars about fifty centimeters wide on the trunks. Or use blackberry vines. That costs nothing. Refrain from using barbed wire, as cats, as well as other "bird lovers" such as squirrels or martens, could dangerously injure themselves on it.
Hang nest boxes so that cats have no access: on facades or freely suspended from side branches and at least two meters above the ground. Nesting boxes with steep, smooth roofs are particularly cat-proof, as they do not provide any footholds.
Place feeders and birdbaths at least two feet from the nearest shrubbery. So cats can’t sneak up on you unnoticed.
Cats have highly sensitive noses. If they can’t stand smells, avoid the scent sources. Cat repellent litter powders are commercially available. The so-called "piss off plant" has become fashionable. This plant with the common nickname, also known as harp shrub (Plectranthus caninus), belongs to the labiates and is available in garden shops. Best to plant near nesting sites. It should keep cats away within a radius of two to five meters. By the way, we do not smell the plant.

Since domestic cats roam larger areas in their search for prey, they naturally do not stop at garden boundaries. Therefore, get into conversation with your neighborhood. Maybe they own a cat and are not as well informed about the problem as you are. Protective measures of individuals are not for the cat, but only if as many garden friends as possible, whether cat owners or not, help the birds, fewer fall victim to domestic cats.