Sitta przewalskii 's territorial calls differ significantly from those of S. leucopsis , whose notes are more nasal , .
The song of Sitta przewalskii   is in long verses composed of whistles that ascend in pitch .
Sitta przewalskii 's territorial calls differ significantly from those of S. leucopsis , whose notes are more nasal , whereas the song of S. przewalskii is in long verses composed of whistles that ascend in pitch .