Seabird Sensory Ecology

An Interview with Ariel-Michaiah Heswell By Louisa Ren

Ariel is a postgraduate student in Marine Biology who recently completed her BSc(Hons) project on seabird sensory ecology with her supervisors Dr Anne Gaskett and Dr Megan Frieshen. The results of this project are expected to be published soon. Currently, she is working on her PhD where she will be studying seabird sensory ecology even further.

Tell us a bit about yourself! How did you get involved with your honours project?

I was born and raised in Brunei, which was a very diverse environment and had very diverse animals. I loved animals and conservation, and when I moved to New Zealand, I took the Bachelors in Marine Science program and absolutely adored animal behaviour. The marine science department did not really focus on the particular animal behaviour I wanted to study for my postgrad, so I changed my major for my PhD to Biological Sciences to study the behaviour of seabirds from a sensory perspective. My supervisor and lecturer at the time was giving a presentation on seabird sensory ecology, which I got really into. Then I did an honours project on it looking at whether certain types of sensory systems and seabirds are more vulnerable to bycatch, why they are more vulnerable to bycatch, and we looked at it from a sensory point of view. It did turn out that actually those seabirds that had a greater and larger sensory system relative to their body size, were more likely to be attracted to fishing vessels, which then increased mortality rate—these were amazing findings. And so I was continuing along the lines of bycatch by adding new avenues into it for conservation of seabirds, including plastics and lights. Right now for a PhD, I’m looking at different types of colours, plastics, and lights, seeing if certain seabirds are more or less likely to become attracted to the plastic. Looking at that from a sensory perspective, why are they being attracted? Is it the size of their sensory system? I’m looking at it from that point of view—I’ve just started and I’m seven months into my PhD.

That’s fascinating! What exactly is meant by seabird sensory ecology?

Ecology is the study of animals and the interactions in their environment; how they interact with things—which can be other animals, or it can be fauna and flora. Sensory is just how they view the world—like from their eyes, their hearing, their sense of smell and vision. So how they interact with their environment using these sensory systems.

Why exactly are seabirds attracted to f

ishing vessels?

So that question is actually really hard to answer. There can be multiple factors and variables as to why they are attracted.

There could be just a sense that they're in the same area, so the fishing vessel and seabirds are competing with each other for the same prize, which is fish or squid or something like that. When the fishing vessels are in the same area as seabirds, there's an increase in interaction rate, therefore they're more likely to be attracted to the fishing vessel. However, the actual studies have shown that sometimes the seabird diverts away from its normal migratory route and foraging area to go directly towards the fishing vessels. There is also the potential that because the fishing vessels are after the same prey as the seabird, as well as the bait and the awful discharges the fishing vessel emits, the chemicals and smells resemble the same odours as the seabirds’ prey and diet. All these good smells for the bird that make them think, “I love the smells, I'm going to go towards it.” Maybe they see that as their chum—which is their diet, and so they're like, “I want to try to grab something off that.”

As for why they're attracted to lights, it is possibly because some of their prey is bioluminescent and lights up, so they're attracted thinking it's food. Another possibility is the seabirds are attracted because they use the celestial bodies such as the moon in the stars for navigation. They may see the light and think, “Oh, I should use that for navigation,” and then collide with the fishing vessel instead.

Were there any particular bird species that were found to be particularly attracted to fishing vessels?

Yes. So there were some studies which have been done in the Hauraki Gulf in New Zealand when they've got MPI (Ministry of Primary Industries) reports, and they found that the black petrel was a high risk species to being attracted towards the boat—this is different from light attraction.

For the bycatch, the highest was once again black petrels and some flesh-footed shearwaters, and I believe some albatross species—I can't remember, but I think it could be the Buller's albatross or something like that. There were definitely seabirds which had less bycatch risk as well, such as the common diving petrel, the fluttering shearwater and the Buller’s shearwater.

With the light attraction, it's interesting because the common diving petrel—which was less caught in fishing gear—was actually more likely to be attracted to the lights, and they were actually caught as deckstrike when they just ram into the boat. And so common diving petrels are one of the highest, and also lots of Cook’s petrels, whereas something like the black petrel is less often attracted towards the light.

How was the research done? Was it all observational or were there experiments involved?

For the honours project looking at bycatch, I went to museums and measured the skull and the wing lengths, and a bunch of body sizes of six different types of seabird species. We had three that were more likely to be at a higher risk of bycatch, and three that had a lower risk of bycatch. I just did a whole ton of measurements of their eye socket sides, nostril socket size, and did some brain scans to look at their olfactory bulbs and their optic tecta. Then I did a morphometric and sensory comparison of the different species to get a correlation of that. For the lighting experiments, I had a lot more range (because we had some permits) to do experimental designs. We went to the outer islands of the Hauraki Gulf, like the Mokohinau Islands, the Little Barrier Island, Tapanui, and Tiritiri Matangi, and we shone different types of lights into the sky; for example, red light, green light, white light, halogen fluoro, and a huge flood light. We counted the number of seabirds that we saw, and we weren't really looking at any particular species, but the species which were most likely attracted to the lights had burrows nearby.

Was there anything that surprised you from your findings?

Hm… something which surprised me, especially with the lights is that so far, we actually haven't found any statistical significance between different colours and attraction towards lights. When we did some more research beforehand into it, it looks like it also depends on other variables, such as the location. If you look at that specific location, there were differences between the lights, but when you combine them, there were no differences—so it's to do with the location as well as the moon phase. We definitely found significant results for the moon phase, which was that when it was a full moon and fully bright, there was less attraction towards the seabed—towards the light by the seabirds, whereas during a new moon and it is completely dark the lights were a lot brighter in comparison and less conspicuous, they were more likely to be attracted.

Did you look into how birds see colour and whether that would affect their attraction to colours and lights?

Yes, that is a very valuable point. Unfortunately, when we want to do that sort of thing and see how the bird sees the colour, the experiment to do that would involve dissecting the eyeball and looking at their rods, cones, and oil droplets—that's only now been done for two species of seabirds. One has just been done in Hawaii, and so [that researcher] is going to publish her work very soon; and another one has been done in Australia. It's really, really hard to do because ou need a freshly killed seabird in order to do it, and the ethics and permit to kill a seabird? Really difficult. Unless it's about to die (because of something else), you're not really going to be able to cut the eyeball and get everything done in time. The [researcher in Hawaii] has been doing this for a very long time so she knows what she's doing and managed to do it, but it’s just going to be really hard to do for us as we’re just starting out.

Did this lead to any new questions?

Yes. So in terms of questions of the moon phase, it also looked at why as well—most likely we would have to do the eyeball [dissection]. But also, the basic [study] we could do is just looking at their sensory size, and what the size of the visual system is. It won't help us with what the bird can actually see, but we can get an idea that if some eyeballs are bigger than the others, maybe that's related as well. It also opens an avenue of what other colours they are attracted to; for example: plastics. Are they attracted to certain colours or types of plastics? So yeah, just looking into that sort of thing as well.

What else did you do during your project?

When I did the honours project I was only able to do one CT scan sample per species, so I only got six. Because it was an honours project and was restricted on cash and time, I could only get a year to do everything, including coursework. I would like to do more of it this year, and I've actually been sending emails to museums in order to do some more CT scans. What I found was very restricting with the CT scan, is that if I try to go to a hospital or clinic to try to get CT scans they all ask, “Why do you want to do that?” Then they just say, “No, I'm not really interested.” And if I go to the bioengineering place it’s great because they understand the scientific research, but at the same time, I'm very restricted with the skull sizes I can scan. I can only give small samples because they can only fit a max. of about 10 to 11 centimeters, and some seabirds are much bigger—they can have about 15 centimeters. For those seabirds like the black petrel and the shearwater, the fluttering shearwater and the common diving petrel—those are really small. But bigger birds, which I want to test in comparison, are much bigger so they can’t fit, so I am attempting to look at other places I can do the CT scans on. And yeah, so I found that very challenging as part of the research for the honours, and I'm probably going to find it challenging in that six month time to a year time [with further research].

So you’re hoping to do more CT scans later on?

Yeah, because I would like to look at the olfactory bulb, and optic tectum. There is a potential way around it—I'm going to do dissections on the brains of the seabirds. That is a potential in case the micro CT scans fail. But I did enjoy doing the micro CT scans, because you actually get a 3D image of the brain and it's really cool to look at and do measurements. What kind of people did you work with during this project?

I worked with museum curators, I worked with people who love to go out to remote islands and do [research]. I worked with rangers from the Auckland Council, the Department of Conservation, as well as my supervisors who know a lot of spectral and colour measurement things—just a variety of different people.

What kind of impact do you hope your research will have in your field?

I'm hoping that I can do some more publications and presentations at conferences, and things that could potentially give some more light to understanding these topics, especially since not many people look at it from a sensory perspective. Not many studies have delved into this sort of area, especially in New Zealand and Australia. Very little is done on plastic ingestion in seabirds in New Zealand, and it's so strange, given how many seabirds we have here. Nothing has been done on plastic ingestion and seabirds—maybe the odd observation but no one's actually done any experiments or published papers on it. It'd be good to actually give [these findings] to the MPI and the primary industries (especially for fisheries) and for example, going to cruise vessels and saying, “Oh, potentially you can use these colours of lights to reduce the attraction rate of seabirds,” especially if you're passing through an island that is known to have burrows. You could dim or change the colour of the lights, or maybe discuss with cruise ships and fishing vessels, as well as with plastic companies.

I haven't done any experiments on this yet but in the next year or so, looking at the plastic and potentially going to people who do the plastic side of things and suggest maybe changing to this certain colour to try and reduce consumption by seabirds and turtles and things like that.

Research aside, did you learn anything else from doing this project?

It really taught me how to manage time to that next level; I did some other projects before, and I thought, “Oh, yeah, I can manage my time alright,” but doing an honours project really teaches you that because you've got to balance your actual coursework, and other papers you're taking, as well as your research, as well as trying to find time for your friends and family. Then there’s also your own time, so you have to go find that balance. It really teaches you to find a balance for your mental health as well as all of your physical health—like going out, doing some exercise, hanging out with some friends as well, going back to see your parents.

It also teaches you a lot more about taking control of the research, because I was very, very scared when I first started. I was like, “Oh, shoot, I don't know, if I'm gonna be able to do this in terms of what if I do it all wrong?” I felt like I needed to ask my supervisor about everything I was doing and I really needed guidance [starting off]. That was the beauty of my supervisor—she was always there to fall back on and guide me. As for my honours project, that really taught me to become more independent and I can now actually design my own [experiments]. Now for the research of this PhD project, I've actually started doing a lot more designing of other projects. I was doing some reading, and I decided that I want to do some experiments with colours and penguins. I brought forth a proposal to my supervisor and she loved it. So yeah, it teaches you how to become a bit more independent in your thinking and if you’re like me, you can start off extremely dependent and super scared and nervous about what to do but in the end, you will grow in confidence.

Do you have any advice for anyone who is hoping to go into research in this field?

You don't have to be a seabird lover at first—I certainly wasn't. I had no idea there were so many different types of seabirds around, like the main albatrosses, cormorants, seagulls and penguins, and then you just open a new research area. Trust me when I say seabirds will grow on you and you'll end up loving them so much.

You also don't have to be someone who loves hiking or is very into getting out to the field to get into seabird research. Sometimes there are things in terms of going out to remote islands, going up and down sheer cliffs. I am personally terrified of heights, so I let some other researchers go up a sheer vertical cliff and I'll just wait down here, and that's all. You don't have to do that in order to do this seabird research because although a lot of fieldwork does involve going out to remote islands, you can also do other things like examining what colours they're attracted to, looking at their digestive tracts or something like that, and looking at their morphology; there are a variety of other things you can do if you're interested in conservation and things. Or if you really do enjoy going remotely and going up vertical cliffs, then yeah, go for it if you enjoy the thrill of that, but there's so many different pathways and avenues you can take. Just be creative, and you and your supervisor will find a project.

What is your favourite seabird?

I love the New Zealand storm petrel. It's such a little cutie and any white-faced storm petrel as well. If you look up a picture, you'll see why they're just so cute. When they skip the surface of the water, the little pitter patter of their feet and fluttering around is so adorable. Also the New Zealand storm petrel, which was actually thought to be extinct until either the late 90’s or early 2000’s when it was rediscovered in Little Barrier Island.

Do we have many of those?

[Their population] is still really small but they are definitely

around as you can see them in the Hauraki Gulf just fluttering around—they're tiny and probably around the size of a dove. Just picture that little thing, skimming the surface, barely touching the surface with their feet and then hopping off again.

Overall, how was your experience while doing this project?

I really enjoyed the seabird research. It's definitely been a journey and adventure and it has definitely given me a greater love for seabirds, as well as for research and showing that I actually really want to do research. For anyone interested in continuing on with research and if you're into this sort of thing, it's really fun. It gives you a sense that, “Oh, I discovered that,” you know? I like that it gives you a sense that you're helping contribute to the scientific world, that you're actually helping your community. So you're actually helping with research and findings to understand how the world works. It's actually real and it's real fun, you'll meet so many interesting people. I've definitely met a whole ton of eccentric people and they’ve been great to work with. It's been a real fun time, definitely challenging. But overall, it's very rewarding.