Meeting Abstract

P2.102  Thursday, Jan. 5  Survival of finches is predicted by oxygen carrying capacity, but not by immunological, stress, or condition parameters MILENKAYA, O.*; WALTERS, J.R.; Virginia Tech; Virginia Tech

While some physiological parameters have been demonstrated to predict reproductive success (eg. MCV) and survival (eg. CORT), others have yet to be validated as indicators of fitness. We investigated whether several such measures were linked to survival probabilities in a population of wild Crimson Finches (Neochmia phaeton) at Mornington Wildlife Sanctuary over two breeding seasons. Adults and nestlings were sampled for hematocrit (PCV), hemoglobin (Hb), and total plasma protein. Adults were additionally sampled for heterophil to lymphocyte ratio, scaled mass index, muscle score, and fat score. We included age, sex, breeding stage and year in some of our models of adult survival, and size and year in some of our nestling models. We analyzed survival in Program MARK and ranked the models using an information theoretic approach. The top two models for apparent adult survival included PCV and, combined, had 66% of the model weight. An adult with high PCV is 250% more likely to survive one year compared to an adult with low PCV. With 79% of the weight, the top two nestling models included PCV and Hb, parameters that are highly correlated and reflect oxygen carrying capacity. High PCV nestlings are 200% more likely to survive to independence compared to nestlings with low PCV. These results indicate that oxygen carrying capacity, but not immunological, stress or condition parameters, predict survival in Crimson Finches. None of the birds were anemic, suggesting that the effect of PCV and Hb on survival is not mediated through direct mortality, but is an indirect effect of oxygen carrying capacity. We hypothesize that increased oxygen carrying capacity may improve predator evasion and competitive ability.