Locascio and Mann: Diel and seasonal timing of sound production by Pogomas cromis 
331 
12/11/05 12/30/05 1/19/06 2/8/06 2/28/06 3/20/06 4/9/06 
Date (2005-2006) 
Figure 3 
Times of chorus start (open circles), chorus end (filled circles), and sunset (solid line) for select time series 
of black drum (Pogonias cromis) sound production recorded at Cape Coral site 3 (CC3, top graph) and 
Punta Gorda (PG, middle graph) during 2005, and Cape Coral site 2 (CC2, bottom graph) during 2005-06. 
(Further details are given in Tables 2 and 3). 
Table 3 
Wilcoxon signed-rank test statistics (T) and P-values of ascending vs. descending slopes and mean and standard deviation (SD) 
of black drum ( Pogonias cromis ) chorus events. Slopes were measured from chorus start time to 6 dB below maximum sound 
production level (SPL) (ascending) and from 6 dB below maximum SPL to chorus end time (descending). Ascending slopes were 
significantly greater for each time 
series. PG 
=Punta Gorda, F 
CC = Cape Coral, FL. 
df= degrees of freedom. 
Site 
Dates 
df 
Chorus 
ascending slope 
Chorus 
descending slope 
Wilcoxon 
P 
Wilcoxon 
T 
mean 
SD 
mean 
SD 
PG 
3/22/04-5/3/04 
25 
2.10 
0.80 
1.50 
0.85 
0.03 
2.4 
PG 
12/12/04-5/4/05 
82 
2.40 
1.44 
1.70 
1.10 
<0.01 
3.1 
CC1 
2/12/05-4/6/05 
42 
3.10 
1.32 
1.70 
0.62 
<0.01 
6.0 
CC2 
2/12/05-5/6/05 
102 
2.90 
0.95 
2.30 
0.87 
0.01 
2.7 
CC2 
12/3/05-6/7/06 
42 
3.00 
1.42 
1.80 
0.90 
<0.01 
7.9 
CC3 
2/12/05-4/6/05 
39 
1.80 
0.85 
1.20 
0.88 
<0.01 
3.2 
time of maximum SPL. Ascending chorus slopes were 
significantly greater than descending slopes for all time 
series (Table 3). 
A distinct seasonal pattern was evident in black drum 
sound production in all acoustic time series, and sound 
production patterns were consistent between years for 
each site (Figs. 4 and 5, Table 4). Subchorus threshold 
levels of black drum calls were recorded as early as the 
third week of October (at CC2 in 2005) and as late as 
the first week of May (at PG in 2004). Sound produc- 
tion first exceeded threshold levels by mid December 
in CC and early January in PG and were last recorded 
in early and late April, respectively (Table 4). Monthly 
mean maximum SPLs were greatest during January 
