Seabirds under environmental pressures: Food supplementation has a larger impact than selenium on chicks exposed to mercury and a viral disease

Although infectious disease outbreaks represent a serious threat for wildlife population viability, the environmental factors that underlie such are poorly investigated. The French Guiana breeding of Magnificent frigatebird Fregata magnificens is subjected to recurrent episodes chicks’ mortality likely caused by viral disease. We hypothesized high mercury (Hg) concentrations may be responsible emergence clinical signs. therefore investigated whether healthy and sick chicks show different Hg in blood. Because essential element selenium (Se) highly depleted during poisoning, we further experimentally tested an increased intake dietary Se has effect on blood levels Hg, increases circulating Se, improves oxidative status chicks. Finally, compared results this experiment with previous food supplementation experiment. Our similar between visible signs were significantly while simultaneously decreased naturally recovered from Both fish experiments blood, only modestly affected. Providing appeared have greater benefits than supplementing pills as, although had impact pills, it also reduced vulnerability disease, possibly reducing nutritional stress providing nutrients.