Variability of alarm call in Spermophilus major and Spermophilus erythrogenys (Rodentia, Sciuridae) within contact zone in Kurgan district

Electroacoustic analysis of alarm calls in Spermophilus major and S. erythrogenys inhabiting Kurgan district and adjacent territories is performed. Variability of the alarm call confirms that both species inhabit the interstream area of the Tobol and Ishim rivers. An integradation zone with stable settlements of hybrids between these species is formed on the Tobol river right bank. The length of this zone from north to south is about 170 km; from west to east - 25 km.