The ORCAA Lab recently returned from the Society for Marine Mammalogy’s (SMM) Biennial Meeting in San Francisco. It was a whirlwind to say the least. Of the 2,600+ marine mammal scientists, professionals, and students in attendance I’d be pretty surprised if more than 10 or 15 escaped the week’s activity without feeling exhausted. This was my first SMM conference and I found myself feeling uncharacteristically nervous.
All of the graduate students in our lab were slated to give either a talk (Myself, Selene, and Samara) or a poster (Niki). We were part of a much larger contingent of researchers from Oregon State (both NOAA and the Marine Mammal Institute) and in such had ample encouragement and feedback on our research and presentations; but this didn’t seem to curb my butterflies.
My talk “Temporal stability of North Pacific humpback whale non-song vocalizations at the decadal scale” is the culmination of the first chapter of my PhD dissertation, and while the title might not convey the scope of what I’m trying to understand about animal communication I knew that I had 12 minutes at this conference to do just that. This talk was my first chance to stand up in front of a room of my peers and tell them something true that I had discovered.
Unequivocoal truth is hard to identify in science. As the questions that we ask grown more complicated, and the body of known scientific literature grows, the ‘simple’ phenomena left for discovery become harder and harder to find. In my dissertation I ask the question: what impact does large vessel noise have on humpback whale acoustic behavior? That is not a simple question. Further, it doesn’t begin to encompass whether that impact if negative, positive, or insignificant. My hope, is that as I sift through the steps to collect the data, ask the question, and analyze the results that I’ll have not only the quantitative skill set to tease out the truth, but the ecological acumen to interpret it in a meaningful way.
But I digress.
Before I can dive into these complicated questions I wanted to ask a simple one. Are non-song calls stable over time? Over the past eight years I’ve had the good fortune of collaborating with an increasing number of marine mammalogists. From these collaborations (and my own field work) I was able to compile a data set of non-song vocalizations in Southeast Alaska that span from 1976 to 2015. Using some simple methods (looking, listening), and some slightly more complicated statistical methods (see my previous publication here) I was able to say definitively that, yes, these calls are stable over time.
Further, I was able to demonstrate that they are stable in different ways. While nearly all described call types were detected across the data set some calls were infrequently used but highly stereotyped, in that their acoustic parameters (pitch, duration, bandwidth, etc.) changed very little over time. Other calls were highly variable, but persistent; meaning that while there was more variability in the acoustic parameters (i.e. some were higher in pitch, or had wider bandwidths) the call type was extremely common throughout all four decades of the study. I proposed that this difference – persistence versus stereotypy – may imply something different about the function of the call.
One of the elements of this study that I love, is its simplicity. While certainly the study is rigorous – many thousands of hours of recordings were sifted through, calls measured and extracted, and a three-part classification method was used to reduce observer bias in determining call types – the study in its most basic form is about listening for something consistent over time… and finding it.
One of my first ecology professors are the University of Alaska once told me, good science should be elegant. I don’t know if my study fits this criteria or not but at the very least it was well received at the conference. Admittedly, this may be in part to a fairly substantial technical snafu that forced me to make a somewhat ridiculous public speaking choice on the day of the talk. On my third slide I have a series of recordings of non-song vocalizations that I intended to play for the audience. When I tapped the ‘play’ button of the first sound… nothing happened. So I swallowed my pride and my humility opened my mouth and imitated the four sounds; the fourth sound is a feeding call that you can listen to below.( I’m closing my eyes and reliving the pounding heart experience of producing this sound to an audience of 200 of my most impressive peers… remember those butterflies I mentioned earlier?).
By the time I’d finished, the audience was clapping (I think there may have been a few hoots out there as well), and my already rosy cheeks were a deep shade of red. But the show must go on (I was only in the introduction after all). I finished my talk with time for questions and applause. I was rewarded with multiple collaboration meetings, a few good laughs (Ocean Alliance’s Andy Rogan even bought me a beer), and an award from the Society itself… for best doctoral presentation.