Leucocytozoon toddi in British sparrowhawks Accipiter nisus: observations on the dynamics of infection

Abstract

Leucocytozoon infection was studied in a breeding population of sparrowhawks Accipiter nisus in the British Midlands. Almost all transmission was apparently ‘vertical’ from adults to young, at the nest site. Parasites largely disappeared from the blood between October and April, reappearing in a ‘spring relapse’ during the nesting season. Infected birds remained infected for life; there was no evidence of reduced longevity in infected birds once they had dispersed from their natal nest site. There was no assortative mating between infected or uninfected males and females. It is postulated that the concentration of birds at the nest site allows transmission by a non-specific vector breeding in the same vicinity. At other times of year the birds are more regularly dispersed and transmission in unlikely to occur.

Keywords :

• Leucocytozoon
• epidemiology
• host density
• Accipiter nisus
• sparrowhawk
• spring relapse