This week, Dispatches from the Field welcomes guest poster Amanda Cicchino, who shares some of her adventures wading through the marshes of QUBS in the dark to record frog songs. For more about Amanda, check out her bio at the end of this post.
I like to compare the frog chorus to a symphony. The orchestra in this case is composed of many different species, each with the same end goal. The timing and frequencies of the noises they make have been molded over time to allow them to be heard simultaneously, yet they still compete with one another. Over the course of the night, the entire chorus comes together and tells a story.
My last field season was done at QUBS (Queen’s University Biological Station) and focused on frog acoustics. As I learned from presenting a poster at the annual Open House, not many people are aware of the different sounds frogs and toads can make. Though some species sound quite pleasant, others present you with ear-splitting, gurgling screams that result in a pounding headache1. Most frogs and toads call during the breeding season as a way to attract mates. Most calling and breeding is done at night in marshes or swamps. My original aim for that season was to record the mating calls of Spring Peepers to supplement a dataset, but I developed a “small” side-project with a lab-mate that would require recordings from each species found at QUBS2. What a shame.
A typical night of sampling involves organization and proper preparation. Prior to leaving for the site, a few cups of coffee must be ingested, with at least one travel mug packed. The field pack must include digital calipers (to measure the frogs), plastic calipers (in case it rains and the digital ones can’t be used), multiple flashlights and headlamps, a heat gun, my notebook and pencil, recording equipment, back-up batteries (in case the ones in the devices die during the night), and emergency back-up batteries (in case the back-ups die or spontaneously combust3). Everything digital is kept in Ziploc bags in case it rains through the car or through the rain-cover on the pack.
Wearing the right attire is also a necessity for a smooth sampling night2. Fashion has always been a priority in my life, and I’m glad to have the opportunity to maintain that passion while sampling. Since the first frogs (typically Wood Frogs) begin calling when there is still ice floating on the marsh, the temperatures I sample in can be quite low. I won’t bore you with specifics of how I dress, but I do want to give you an image of how I feel I look. (But also stuffed into brown neoprene chest-waders). Of course, dressing with that many layers might impede my speed and agility in the marsh, so I tend to invest in good thermal clothes.
Once the sun sets, a few individuals will start to call until the peak is hit and the chorus is in full swing. My sampling begins at the peak and ends either when I have transected the whole marsh, reached my sample size limit for the site, or the chorus goes silent (usually the last one). I record every individual I come across for at least 20 consecutive calls using a Marantz PMD660 recorder and Sennheiser microphone. This can look quite humourous as the microphone is at least 30cm long and some frogs are approximately 2cm in length. I then catch the individuals and take morphometric measurements before releasing them. This can be a slow process as some individuals are “mic shy”. When they stop calling once the microphone is put near them, my general tactic is to turn off all my lights, splash a bit, and wait. Usually after a minute, they start calling again and I can feel good about myself for out-smarting a 2cm long frog. This tactic does not have to be employed too often, as I find that frogs can be quite bold. In fact, on more than one occasion, I have witnessed a frog making mating calls when the lower half of its body was inside a snake’s mouth. Once I have finished my sampling, exhausted and exhilarated, I look forward to reliving the night when I analyze the call recordings the next day.
Perhaps comparing a frog chorus to a symphony seems a bit quixotic, but they do have some similarities. They both require a specific dress code, they both overlay impressive sounds and rhythms, and they both tell an extravagant story. Of course, the frog chorus’s story is one of acoustic niche and evolution, but that is one of the most interesting stories I can think of! This kind of field work isn’t for everyone, but I truly love it. Nothing compares to standing in the middle of a marsh during peak breeding season, with a full chorus of hundreds of frogs desperately calling to attract a mate. The frog chorus is quite literally music to my ears.
- Google ‘Bird Voiced Tree Frog call” and “American Toad call” for this comparison. You may want to make sure your speakers are turned a bit low for the latter.
- Please beware of extreme sarcasm used ahead.
- A pessimistic mindset leads to the best preparation.
Amanda recently completed her BScH at Queen’s University, researching acoustic divergence in the Spring Peeper for her Honour’s thesis. She is starting her MSc at Queen’s this fall, and will continue to study the role of mating systems on speciation.