Scientists have found that because of the fear of predators, some birds raise their chicks worse

(ORDO NEWS) — Canadian scientists have found that if sparrows constantly feel the proximity of a predator, then they carry fewer eggs and feed their chicks worse, which either die or grow weak because of this.

Because of the fear of being eaten, parent sparrows do not take good care of their children.

The fear of predators alone is enough to reduce the sparrow population by several times – this is the main result of a study conducted by scientists from the University of Western Ontario (Canada).

Predators are known to slow down the population growth of various species by preying on and killing birds and small animals.

However, it turned out that they can have not only a direct impact on the reduction in the number of individuals, but also an indirect one – their presence on the territory is enough for potential victims to feel uncomfortable and multiply worse.

To mimic the presence of natural predators, Canadian researchers conducted an experiment. They hung speakers in the trees, through which they broadcast the natural sounds of predators – the calls of hawks, ravens and raccoons, and observed the behavior of sparrows nesting nearby.

For the purity of the experiment, they included the cries of geese, a species that does not pose a danger, to other sparrows.

The speakers were regularly moved and the audio recordings changed slightly so that the sparrows would not get used to them. At the same time, all sparrow nesting sites were protected from real predators by electric fences, so there was no real threat.

In the end, it turned out that sparrows that were constantly frightened by the sounds of predators raised 53% fewer reproductive offspring than their counterparts who felt safe. Previous research has shown that fear of predators reduces the number of eggs birds lay, but scientists didn’t know what other effect they might have.

The researchers explain their new results as follows: when sparrows constantly hear the sounds of predators, they spend more time on “duty” – they control whether a raccoon, crow or hawk has approached. Accordingly, because of this, they are less likely to look for food.

No food – no energy to lay a large number of eggs and raise chicks. And little sparrows also suffer from lack of food and either die or grow up very weak, becoming easy prey.

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