Links between blood parasites, blood chemistry, and the survival probability of nestling American crows

1. Many studies have used the avian haemosporidians (Leucocytozoon, Plasmodium, and Haemoproteus) to test hypotheses of host-parasite co-evolution, yet documented health and survival consequences of these blood parasites vary among studies and generalizations about their pathogenicity are debatable. In general, the negative effects of the haemosporidians are likely to be greatest during acute infections of young birds, yet most previous studies in wild passerines have examined chronic effects in adults. 2. Here, we evaluated responses of nestling American crows (Corvus brachyrhynchos) to acute infection (prevalence and burden), as well as its short- and long-term survival consequences. 3. We used panel of nine hematological and biochemical parameters that are regularly used to evaluate the health of domestic animals, including leukocyte profiles, hematocrit, and plasma proteins. We assessed the effects of infection on survival in a mark-recapture framework. 4. Overall, 56% of crows (n =...