The use of poison to kill predatory animals occurs in almost every country in the world. In the past, "natural" poisons, such as wolfsbane, were used. Today, modern pesticides - above all insecticides - are more common. Victims are almost always birds of prey.
The perpetrators usually use dead wild animals, slaughter waste or chicken eggs to bait and poison birds. Since baits are also used legally for hunting, e.g. to attract foxes, it is not always easy to distinguish them from illegal poison baits. It only becomes clear that poison is involved when dead birds are found next to the baited remains. There is also a method which involved coating live pigeons with poison and letting them fly. This way, falcons and hawks, which rarely eat carrion, are more easily killed.
Victims are often scavengers like Red Kites, which weren't the target of the perpetrators. In Spain and in the Balkans, poison baits are still used for stray dogs, foxes and (only in the Balkans) jackals, but they mostly affect eagles, vultures and buzzards.
There is often a link with hunting in cases of poisoning. However, poison-attacks with live pigeons, are generally done by pigeon-fanciers and mammal-lures in Spain and the Balkans are laid out by livestock farmers.
It is often mistakenly assumed that the improper use of insecticides in agriculture can poison birds or other vertebrates. That is not the case! In agriculture, poisons are applied to crops in liquid form, while poisoners who intentionally want to kill animals lay out specially prepared meat baits.