Fig. 1

The range expansion of the Australian House Sparrow. The map (a) is a redrawing of a distribution map published by Summers-Smith (1963) which estimated the distribution of Australian House Sparrows in 1960. The map (b) is a redrawing of a map by Jones (1986) which uses multiple sources of information to estimate the distribution of the House Sparrow in Australia at different time points and displays the range growth using contour lines. Jones’ 1960 distribution line seems to follow Summers-Smith’s distribution. The map (c) was generated from our research which collected the arrival time of House Sparrows in different towns and cities (see Additional file 1: Table S4 for full details). The map (d) uses our arrival points to draw our own contour lines which estimate the species range expansion between different time intervals in a comparable way to Jones (1986)