ECR Spotlight – Juan Zuluaga

Juan Zuluaga

How would you explain the main finding of your paper to a member of the public?

The main finding of the paper is that stress, such as you yourself may feel if encountering a predator in the wild, can reduce the efficiency with which birds get rid of heat on hot days. To understand how this happens, we must first understand how birds get rid of heat using two important pathways.

Birds can use evaporative heat loss by panting, which accomplishes the same function as sweating in humans (evaporation requires energy and when water molecules evaporate from a surface the process ultimately cools the surface that the water evaporated from). Birds can also use dry heat loss, which is the main focus of this study. Dry heat loss happens when a part of the body is heated up above the temperature of the air, which then causes heat to move from the body part to the air. Birds accomplish this by increasing blood flow and it works particularly well in the bill and any body parts that are (i) not insulated, (ii) have lots of blood vessels and (iii) have a large surface area; these are the defining characteristics of a thermal window, or a body region that can effectively exchange heat with the environment.

In this study, we found that the surface temperature of the beak was initially high, and then decreased when the bird experienced stress. This likely happened because stress has been found to cause constriction (in other words, tightening) in blood vessels near the surface in other organisms and this constriction of blood vessels causes less blood flow, which in turn lowers the temperature at the surface. This is an important finding because it means that when birds experience stress, they are regulating their body temperature less effectively, and humans can cause stress by disturbing them. Furthermore, it is important because dry heat dissipation, as its name implies, doesn't require water and therefore provides birds with important resource savings, which can be lost when the bird experiences stress.

What do you think experimental biology will look like 50 years from now?

An overarching goal of my PhD research is to showcase the potential of experimental biology for conservation and wildlife management. I also hope to create predictive models for a species that I suspect is at great risk from climate change. Studies such as those by Albright et al. (2017; doi:10.1073/pnas.1613625114), Conradie et al. (2019; doi:10.1073/pnas.1821312116) and Conradie et al. (2020; doi:10.1093/conphys/coaa048) show the impact that can be made by combining climate modeling with the fine details that experimental biology yields. I hope to contribute to this growing body of literature by integrating experimental biology with species-specific conservation-oriented goals. I hope this type of research will be more common 50 years from now.

What's next for you?

I've got a lot of work to do and I'm loving it. I'm wrapping up the data collection and analyses and have begun writing for my next manuscript. I'm really excited about this one because it relates to seasonal variation in avian thermal biology, which is a subject that has not received a lot of attention in the literature relative to other avian physiology topics. In their review of thermal physiology, McKechnie and Wolf (2019; doi:10.1152/physiol.00011.2019) draw attention to this and I am very excited to contribute to the filling of this gap in knowledge. I'm also excited about this research because it involves a species that has not been studied in this context, the chipping sparrow (Spizella passerina), and the research was conducted in a unique region for studies of bird thermal physiology. This research took place in southeastern North Carolina, which is relatively humid compared to the arid regions where this type of research has typically been conducted.

What perspective would you like to share with people of colour who may be curious about science as a career path?

As immigrants and/or people of color, we are lucky because we get exposed to a lot of unique and often difficult situations, and this diversity in experiences is helpful because science is a career that demands both adaptability and perseverance. Growing up, my family couldn't afford day care, so my parents often took me to work with them, which I am thankful for because it got me thinking and problem solving early on. By the age of 6, I was accompanying my father to his work as a satellite TV technician; I knew the tools in his tool belt and I could fetch him whatever he needed as long as it wasn't too heavy. I accompanied my mother to her job as a vendor for prepaid long-distance phone call cards, where I was exposed to other immigrants from all over the world and their languages. My parents worked countless other jobs, from cleaning houses to repairing watches, until they started a moving company when I was 12. I started formally working as a mover after school, on weekends and over summers, which, in addition to having some spending money, had its benefits.

In science, we often say that we ‘stand on the shoulders of giants’, and this is true. As immigrants and minorities, we not only stand on the shoulders of giants, but on the shoulders of explorers, dreamers and hard workers. That is a lethal combination for a scientist and it is our defining strength. Use it.