It seems to be a good time to post a research update coming from the auditory physiology side of the project. I’m currently wrapping up a research trip to Europe, where I worked on multiple different components of the project with the other team members in the UK and Netherlands. Olivier and I also had a productive visit to a bird hearing expert earlier this week in Oldenburg, Germany.
I have been reviewing the scientific literature on low frequency hearing in birds, including the various experimental studies and hypothesized detection mechanisms. There are indeed many factors that can control the detection of low frequencies by birds. Sound vibrations move through the middle ear, inner ear, and auditory hair cells, ultimately becoming encoded into a neural signal at the end of the transmission line. At each of these levels, there are distinct structure-function relationships that will affect signal transmission. There is likely no single anatomical marker that will precisely reflect infrasonic hearing abilities, but the relevant anatomical parameters and how they might be expected to affect low frequency transmission is becoming clearer.
Multiple building blocks need to come together to pursue the big question, “do seabirds detect infrasound?”. One of these building blocks is a quantification of the large-scale patterns of auditory anatomy in seabirds. For this goal, I have been collecting microCT scans of seabird heads and skulls. In general, not a lot has been described on the auditory anatomy of seabirds.
The microCT images are quite cool to view and analyse. Below are microCT images of white-chinned petrel, Procellaria aequinoctialis (A). This species is commonly caught as bycatch from long-line fisheries vessels operating in South African waters, and that was my source for this particular specimen (thanks to folks at Capfish and BirdLife). You can even see a fish still in the throat and a bit of the hook apparatus on the lower right. Here are some additional images showing the reconstruction process for this technique. You can see clearly on this image the columella (middle ear bone of birds) and inner ear (B). After some analysis, the 3D models of specific components can be reconstructed (C,D).
One possible further application of the comparative microCT data is to use the 3D surface models to simulate acoustic transmission properties of the ear. This can be an option for animals for which direct hearing assessments are difficult, such as whales. The simulation models are then verified by direct vibrometric observation of middle ear. This technique might be a useful method for testing between the performance of different routes of acoustic stimulation. For example, the vibration transmission performance of the middle ear in tetrapod animals (including birds) generally declines towards low frequencies. Alternatively, sound at these very low frequencies might effectively couple to the whole body of the bird itself.
After some delay with getting permits to collect seabird heads (partly due to restrictions related to the bird flu striking earlier in the year), we have the permissions we need and I hope to be examining many more species soon.
From 14 till 17 May the first SeabirdSound workshop took place in Liverpool. The workshop focussed on infrasound and avian navigation and is part of the HFSP Project (investigating the role of infrasound in seabird navigation; it combines seabird ecology, physiology, infrasound soundscapes, and movement ecology in a comprehensive framework).
For the workshop, we brought together experts in all of these areas to share expertise and integrate ideas. In particular we were keen to discuss avian navigation in general with a focus on seabirds. By use of keynote presentations and engaging discussions, we developed an integrated framework around the use of infrasound in navigation and developed a begin for a review article around this subject. Follow the website for more news about this article.
We would like to thank all participants (alphabetic);
Simon Benhamou, Jakob Christensen-Dalsgaard, Annette Fayet, Jon Hagstrum, Christine Koppl, Emiel van Loon, Pascal Malkemper, Richard Phillips, Mark Prior, Pieter Smets and Yoshinari Yonehara.
And in particular Tommy Clay and Samantha Patrick for taking lead in organising!
From 8 till 13 april the European Geosciences Union (EGU) organised the 2018 General Assembly in Vienna (Austria). During the assembly 4.776 oral, 11.128 poster, and 1.419 PICO presentations were given.
Jelle and Olivier represented the SeabirdSound team, both gave a poster presentation. Jelle presented his research about the Dutch Meteo-Tsunami of 29 May 2017. Olivier presented his studies on parameterising the CLEAN beamforming method on infrasound recordings.
Besides presenting, both participated many interesting presentations and short courses. It was an interesting week, good weather, good science and a good environment!
We are seeking a motivated MS student to join our team in Florida, aiming at understanding how seabirds navigate and the role of infrasound in their movement. The MS thesis will follow one of two possible paths, requiring students with two distinct profiles: one in applied statistics/mathematics; and one in quantitative ecology. Applications are encouraged for both profiles, but only one student will be selected.
The Master’s program will consist of three semesters mainly dedicated to classwork during the first year and a second year exclusively dedicated to the Master’s thesis. This position will be completely supported for the two years (stipend + tuition) and the program is expected to start in fall 2018.
Classwork during the first two semesters will take place on the main UF campus in Gainesville. Research will be performed at Dr. Mathieu Basille’s lab, under the supervision of Dr. Basille and Dr. Rocio Joo. Dr. Basille’s lab is located at the University of Florida’s Fort Lauderdale Research and Education Center (FLREC), in Davie, Florida. Davie is a town within the large Miami metropolitan area in South Florida, just miles away from the Florida Everglades.
Full description; MasterAdvert-UF
!!please read the whole advertisement before sending your application!!
Please apply by sending an email including a cover letter describing your interest, experience and career goals, a CV, unofficial transcripts and GRE scores, and contact information for three references to Dr. Rocio Joo (firstname.lastname@example.org). Write “master application” as the email subject. Applications will be processed in the order they are received until April 15th or before if a suitable applicant is found.
Since the start of 2018 the whole team is full time working on the project. Let me introduce;
Tommy Clay (University of Liverpool ,UK)
Tommy is interested in the ecology and conservation of marine predators; in particular, the drivers of variation in movement and foraging strategies and their influence on population dynamics. During this project he will be linking seabird movement data to meteorological and infrasound maps in order to better understand movement decisions at various ecological scales.
Jeff Zeyl (Stellenbosch University, South Africa)
Jeff’s research interests centre on mechanisms of hearing and acoustic communication in vertebrates. Some of his recent work has involved auditory tests on turtles, salamanders, and fishes using the auditory brainstem response. In this project, Jeff will be exploring potential mechanisms of infrasonic hearing in seabirds.
Rocío Joo (University of Florida, USA)
Rocío is a numerical ecologist. Her research is focused on movement ecology; particularly on the development and adaption of statistical methods for the analysis of trajectories of animals and human predators (i.e. fishers). The analysis of different types of tracking data for seabird movement, and the assessment of the role of infrasound in migration through statistical modelling are two exciting challenges of this project that will enrich her research.
Olivier den Ouden (KNMI, the Netherlands)
Olivier will focus on infrasound. Previous he already got experienced with processing infrasound recordings and localisation of infrasound sources. During this project he will exploring infrasound propagation through atmosphere and creating soundscapes.
Since all team members are on board, a first ‘real-life’ meeting was needed. The second week of 2018 the whole team visited the Stellenbosch University in South-Africa, and thus this week can be seen as the official start of the Seabird Sound project! Goal of the week, introduction on previous work, future plan for the project and to get to know each other.
During the week everybody showed their skills and discussed what and why it contributes to the project. A good start with many new thoughts. Besides hard work and discussing, there was also time to relax. With some good wine, magnificant views, wild life, table mountain, seabirds, infrasound and really good company this was not very hard.
After 8 days of hard work and discussing, all went home with new ideas and a lot of motivation. Next meeting, May 2018 – Liverpool!
After a few months of interviewing candidates, Skyping, setting up forms and agreements and more Skyping we have now finally started with the project! The team is now complete – so with a group of 8 enthousiast researchers in total we’re now off to unravel the mysteries of seabird navigation, potentially linking the fields of geophysics and biology!