Fullagar, P. J., Davey, C. C. and Rushton, D. K. (1990) “Social behaviour of the Freckled Duck Stictonetta naevosa with particular reference to the axle-grind”, Wildfowl, pp. 53–61. Available at: https://tidsskrift.dk/Wildfowl/article/view/154047 (Accessed: 17 December 2025).