Ricinus bombycillae, a species of chewing lice in the Ricinidae family, parasitizes birds such as the Bohemian waxwing (Bombycilla garrulus). These bird lice attach themselves to the feathers and skin of their host, feeding primarily on dead skin, feathers, and other debris. While lice infestations may not directly cause severe illness, they can significantly impact the bird's health and behavior.

The presence of Ricinus bombycillae can lead to chronic irritation, causing the bird to scratch and preen excessively. This constant grooming can reduce the bird's overall energy reserves, affecting its ability to forage and engage in essential activities like courtship and migration. Furthermore, infestations can cause damage to feathers, compromising the bird's ability to fly efficiently and, in severe cases, leading to feather loss. Such conditions can make the bird more vulnerable to predators and less able to cope with environmental challenges, including extreme weather or food scarcity.

Additionally, lice may affect the host's immune system, making it more susceptible to secondary infections, although this impact is often more significant in young or already weakened birds. Overall, the parasitism by Ricinus bombycillae negatively influences the health and reproductive success of the Bohemian waxwing.