Table 2. Duration of song bouts and peak song amplitudes for each background noise condition, and correlation coefficients of song amplitude and bout duration for each individual.

			Background noise level
Bird ID	N	Min – Max	50–54 dB	66–68 dB	70–74 dB	80–86 dB	ρ	P
G16*	57	Song amplitude (dB(A))	73.6–82.5	92.2–94.1	97.0–107.6	108.3–115.1	0.057	0.675
		duration (s)	3.07–13.49	1.95–5.16	2.88–14.38	3.63–13.51
G62*	13	Song amplitude (dB(A))	86.5–86.4	-	94.9–96.1	106.2–107.7	0.183	0.550
		duration (s)	1.63–1.65	-	1.02–2.94	0.81–2.08
G68*	55	Song amplitude (dB(A))	80.1–81.4	92.5–94.8	96.0–97.1	102.2–109.1	0.048	0.728
		duration (s)	0.65–3.97	0.69–5.48	0.98–4.67	0.84–2.99
G18	21	Song amplitude (dB(A))	76.1–88.4	90.8–95.6	96.9–98.0	100.1–100.2	0.047	0.840
		duration (s)	1.49–5.35	0.51–6.96	1.76–7.16	2.69–3.47
G36	60	Song amplitude (dB(A))	75.1–81.7	91.2–94.3	87.5–99.4	101.9–103.9	0.110	0.401
		duration (s)	0.78/7.28	1.05–6.67	0.29–2.75	1.06–2.28
Y42	33	Song amplitude (dB(A))	89.0–89.9	-	90.1–96.1	98.1–107.0	0.251	0.128
		duration (s)	0.56–2.46	-	1.97–4.35	0.36–7.19

^*Recordings made while bird was in the respirometry helmet.