1. Allison Wells1, John Peterson1, Gary Casper2
1University of Wisconsin-Platteville, 2University of Wisconsin-Milwaukee Field Station
• Bridges and Dorcas 2000. Copeia. 2:587-592.
• Crouch and Paton 2002. J. Herp. 36:185-192.
• Dorcas et al. 2009. In: Amphibian Ecology and Conservation, Ed. Dodd.
• Lotz and Allen 2009. J. Wildlife Management 71:675-679.
• Runkle et al. 1994. Behav. Ecol. 5:318–325.
• Shirose et al. 1997. Herpetologica. 53:312-320.
• USGS 2015. https://www.pwrc.usgs.gov/Frogquiz
• WDNR 2010. http://dnr.wi.gov/files/PDF/pubs/er/ER0666.pdf
BACKGROUND
• Automated recording systems (i.e. frog loggers, song
meters) record anuran reproductive vocalizations (Fig.
1A; Dorcas et al., 2009).
• Automated surveys are impacted by observer bias that
is often unaccounted for (Lotz and Allen, 2009).
• Little is known about the hourly and seasonal calling
intensities of amphibians, even though it has important
implications for population monitoring (Bridges and
Dorcas, 2000; Crouch and Paton, 2002).
• Blanchard’s cricket frog (Acris blanchardi) is
endangered in Wisconsin and declining in the northern
parts of its range (Fig. 1B, WDNR 2010).
Conduct automated recording surveys of a frog community
including state-endangered A. blanchardi and document:
1. Inter-observer agreement on presence
2. Daily calling intensities
3. Seasonal calling intensities
Figure 2. Percent of cases in which 16 novice surveyors agreed with an expert (author JDP) on the
presence of a species on 10 randomly selected recordings. Sample size indicated above bar graphs.
•Collected recordings of frog calls from 5/13/15 – 8/19/15 at an oxbow lake
in southwest Wisconsin.
•16 novice surveyors (students from an undergraduate research class at UW-
Platteville) were trained for 1h on the frog calls of Wisconsin (USGS, 2015).
•Novice surveyors and an expert (author JDP) listened to 10 randomly
obtained recordings from the study site and determined anuran
presence/absence by species.
•Inter-observer agreement was determined by adding the number of cases in
which novices agreed with the expert for presence and then divided by the
number of cases in which the species was present.
•Hourly calling intensity was determined by listening to files from 1300h to
300h the following day for 16 days between 5/25/15 – 6/30/15 and
recording call indices for all species (see call indices below).
•Frog call intensities throughout the season were determined by quantifying
call indices at 2200h for 5/13/15 – 8/19/15.
•Call indices:
1 = individual frogs calling, no overlapping of calls
2 = individual frogs calling, overlapping of calls
3 = individuals can not be determined, full chorus
Figure 3. Average hourly calling indices throughout the day. No recordings were collected between
0400 hours and 1200 hours. Error bars indicate standard error and n=16 for each time point.
Figure 4. Average call intensities by week (mid-May through late-July at 2200h). Error bars indicate
standard error. Dotted lines indicate polynomial trend lines.
INTER-OBSERVER AGREEMENT
• Inter-observer agreement on presence was generally high
for species with larger sample sizes.
• Results mirrored those of Shirose et al., (1997).
• Few surveys of anuran calls report inter-observer
agreement data (or observer error of any kind), which
may impact models built on previously published call
surveys (Lotz and Allen, 2009).
HOURLY CALLING
• Each species displayed different hourly calling behavior.
• Both A. blanchardi and H. versicolor calling significantly
increased at 2100h and peaked after.
• A. blanchardi calling peaked longer than H. versicolor.
• L. clamitans called relatively more during the day and didn’t
peak until 100h.
• Results mirrored those of Bridges and Dorcas (2000)
SEASONAL CALLING
• Each species displayed different seasonal calling
behavior.
• A. blanchardi called more intensely for a shorter season.
• H. versicolor called at a lower intensity for longer.
• L. clamitans called at the lowest intensity for the longest.
• Results may reflect differences in size, energy stores,
and optimum body temperatures for calling (Runkle et
al., 1994).
RESULTS DISCUSSION
LITERATURE CITED
ACKNOWLEDGMENTS
METHODS
Figure 1. Automated recording system recording an A. blanchardi call. B) Current Wisconsin range
of state-endangered A. blanchardi (WDNR).
A. B.
GOALS
• Scholarly Activity Improvement Fund
• Pioneer Academic Center for
Community Engagement
• Pioneer Undergraduate Research Fellowship
• Sammie Tomczewski and Katherine Macco-Webster
• BIOL 2420 students