title: Flight performance of western sandpipers, Calidris mauri, remains uncompromised when mounting an acute phase immune response.
abstract: Migratory birds have been implicated in the spread of some zoonotic diseases, but how well infected individuals can fly remains poorly understood. We used western sandpipers, Calidris mauri, to experimentally test whether flight is affected when long-distance migrants are mounting an immune response and whether migrants maintain immune defences during a flight in a wind tunnel. We measured five indicators of innate immunity in 'flown-healthy' birds (flying in a wind tunnel without mounting an immune response), 'flown-sick' birds (flying while mounting an acute phase response, which is part of induced innate immunity), and a non-flying control group ('not-flown'). Voluntary flight duration did not differ between flown-healthy and flown-sick birds, indicating that mounting an acute phase response to simulated infection did not hamper an individual's ability to fly for up to 3 h. However, in comparison to not-flown birds, bacterial killing ability of plasma was significantly reduced after flight in flown-sick birds. In flown-healthy birds, voluntary flight duration was positively correlated with bacterial killing ability and baseline haptoglobin concentration of the blood plasma measured 1-3 weeks before experimental flights, suggesting that high quality birds had strong immune systems and greater flight capacity. Our findings indicate that flight performance is not diminished by prior immune challenge, but that flight while mounting an acute phase response negatively affects other aspects of immune function. These findings have important implications for our understanding of the transmission of avian diseases, as they suggest that birds can still migrate while fighting an infection.
authors.affiliation: Department of Biology, Advanced Facility for Avian Research, University of Western Ontario, London, ON, Canada, N6A 5B7. snebel2@uwo.ca
authors.forename: Silke
authors.initials: S
authors.lastname: Nebel
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Buehler
authors.forename: Alexander
authors.initials: A
authors.lastname: MacMillan
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Guglielmo
mesh_terms: D000210:Acute-Phase Reaction / Q000276:immunology*; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001955:British Columbia; D046091:Charadriiformes / Q000276:immunology* / Q000502:physiology*; D005426:Flight, Animal / Q000502:physiology*; D006242:Haptoglobins / Q000378:metabolism; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate / Q000276:immunology*; D016014:Linear Models; D013053:Spectrophotometry; D013997:Time Factors
chemical_list: D000906:Antibodies; D006242:Haptoglobins
keywords: Calidris mauri; innate immune function; trade-off; western sandpiper; wind tunnel; zoonotic diseases