Blood parasites significantly reduce the survival of nestlings

In the wild, the first few weeks of a bird's life are a desperate race against biology. While predators and starvation are the most visible threats, a hidden battle takes place within the bloodstream. Great tit nestlings are frequently targeted by biting insects that transmit blood parasites, including those responsible for avian malaria. These microscopic invaders do more than just hitch a ride; they actively drain the host's resources, leading to a measurable drop in hemoglobin levels.