@misc{9224992,
  abstract     = {{Increasing numbers of species face long-term population declines as a consequence of human activities, and these pressures are expected to intensify under a changing and warming climate. Ground-nesting birds in agricultural landscapes are particularly vulnerable, including the Montagu’s harrier (Circus pygargus), which has declined across Europe due to intensive modern agriculture combined with the loss and overgrowth of natural nesting habitats. Although conservation measures have improved breeding success in several populations, including the Swedish population, long-term survival remains uncertain. Emerging threats, including infectious diseases such as foodborne pathogens and blood parasites causing avian malaria, may pose additional risks to this already endangered population, as such infections are expected to play an increasing role among raptors under changing environmental conditions. However, it remains unknown whether these pathogens are already present in the population and whether they influence breeding success, survival and condition. To investigate this, prey remains, morphological measurements, fecal swabs and blood samples were collected and analyzed during the 2023 and 2025 breeding seasons on Öland, Sweden. The results revealed a diverse gastrointestinal bacterial community, including antibiotic-resistant bacteria, but no evidence of avian malaria infections. Patterns of bacterial occurrence appear to reflect ecological exposure, with bacteria representing the primary pathway of pathogen exposure. Overall, infectious diseases do not appear to currently threaten the long-term persistence of the population. Factors such as dietary exposure, shared environmental background, social transmission within families, host-filtering, habitat selection across breeding and overwintering grounds, species-specific resistance and migration-associated selection seem to explain the observed patterns. How this situation will change in the future remains uncertain, highlighting the importance of long-term monitoring to detect changes at an early stage and safeguard the Montagu’s harrier as a breeding species in Sweden.}},
  author       = {{Lindström, Clara}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Recovery at risk? The role of infectious diseases in condition, survival and breeding success in farmland-nesting Montagu’s harriers (Circus pygargus)}},
  year         = {{2026}},
}