Figure 1. Wake topologies for one wingbeat of the studied species flying at 7 m/s.

The vorticity iso-surfaces (blue: +ω_{x iso}; red: −ω_{x iso}) show the main vortex structures, while the color-coded surface shows downwash w (see color bar). (A) Wake of pied flycatcher #1, ω_{x iso} = ±50 s⁻¹ and w_max = 1.7 m/s; (B) female Pallas' long-tongued bat with ω_{x iso} = ±50 s⁻¹ and downwash scale w_max = 2.1 m/s; (C) the blackcap, ω_{x iso} = ±70 s⁻¹ and w_max = 3.0 m/s; (D) female lesser long-nosed bat, ω_{x iso} = ±45 s⁻¹ and w_max = 2.4 m/s. The wind tunnel coordinate system {x,y,z} and freestream velocity vector U are in panel (B) and (C), respectively.