Frequency just below 6 kHz, good enough for COFL.

Discontinuous phrase 2, like most Warner birds. (Compare to right-most example for COFL.) Tick frequency below 3 kHz = COFL. Maximun frequency higher than previous bird, too high for COFL. Rounded top = COFL. Overall, closer to COFL, but frequency too high.

COFL-like. Frequency within COFL range. Middle note is rather faint for COFL, but it is still louder than the tick.

Intermediate. Initial frequency below 4 kHz (COFL) and terminal frequency above 6 kHz (PSFL). Absence of break and high terminal frequency suitable for PSFL, but PSFL typically descends in frequency in the middle where this note rises.

The only way to distinguish COFL and PSFL FPNs is frequency, and the frequency of this one, below 7 kHz, is right for COFL.