title: Drowning is an apparent and unexpected recurrent cause of mass mortality of Common starlings (Sturnus vulgaris).
abstract: Drowning is infrequently reported as a cause of death of wild birds and such incidents typically involve individual, rather than multiple, birds. Over a 21-year period (1993 to 2013 inclusive), we investigated 12 incidents of mortality of multiple (2 - 80+) Common starlings (Sturnus vulgaris) in Great Britain that appeared to be due to drowning. More than ten birds were affected in ten of these reported incidents. These incidents always occurred during the spring and early summer months and usually involved juvenile birds. In all cases, circumstantial evidence and post-mortem examinations indicated drowning to be the most likely cause of death with no underlying disease found. A behavioural explanation seems likely, possibly related to the gregarious nature of this species combined with juvenile inexperience in identifying water hazards. A review of data from the ringed bird recovery scheme across Great Britain (1909-2013 inclusive) of both starlings and Common blackbirds (Turdus merula), also a common garden visitor, identified additional suspected drowning incidents, which were significantly more common in the former species, supporting a species predisposition to drowning. For each species there was a marked seasonal peak from April to August. Drowning should be included as a differential diagnosis when investigating incidents of multiple starling mortality, especially of juveniles.
authors.affiliation: Institute of Zoology, Zoological Society of London, Regents Park, London, NW1 4RY, UK.
authors.forename: Becki
authors.initials: B
authors.lastname: Lawson
authors.affiliation: Animal &Plant Health Agency, Penrith, Cumbria, CA11 9RR, UK.
authors.forename: J Paul
authors.initials: JP
authors.lastname: Duff
authors.affiliation: Institute of Zoology, Zoological Society of London, Regents Park, London, NW1 4RY, UK.
authors.forename: Katie M
authors.initials: KM
authors.lastname: Beckmann
authors.affiliation: University of Liverpool, Leahurst Campus Neston, South Wirral CH64 7TE, UK.
authors.forename: Julian
authors.initials: J
authors.lastname: Chantrey
authors.affiliation: Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire, SG19 2DL, UK.
authors.forename: Kirsi M
authors.initials: KM
authors.lastname: Peck
authors.affiliation: Animal &Plant Health Agency (APHA), APHA Weybridge, New Haw, Addlestone, Surrey, KT15 3NB, UK.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Irvine
authors.affiliation: British Trust for Ornithology, The Nunnery, Thetford, Norfolk, IP24 2PU, UK.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Robinson
authors.affiliation: Institute of Zoology, Zoological Society of London, Regents Park, London, NW1 4RY, UK.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Cunningham
mesh_terms: D000818:Animals; D000835:Animals, Wild; D002423:Cause of Death; D004332:Drowning; D008168:Lung / Q000473:pathology; D012189:Retrospective Studies; D012621:Seasons; D046749:Starlings / Q000502:physiology*; D006113:United Kingdom