Magellanic penguins (Spheniscus magellanicus) have highly variable reproductive success, and while most eggs successfully hatch, about 50% of the chicks survive to fledging. What determines which of the two chicks in a brood fledges? Typically the first chick hatches two days before its sibling, and has an early size advantage in terms of weight. We predict that larger chicks will occupy the preferred nest position, switching from the warmer position early in development to the optimal feeding position. We also expect that chicks more often found in the “better” position at these different stages will be more likely to fledge. To assess optimal nest positioning we collected weight, nest position, and fledging data on over 1,200 chicks during the 2017-18 Magellanic penguin breeding season at Punta Tombo, Argentina. We extracted data from our SQL Database using a number of SQL queries, and we will use R Studio to analyze our results. We expect to find larger chicks preferentially in the back (warmer) position of the nest early in growth for better thermoregulation, and in the front of the nest later in development since they would be closer to the adult’s head during feeding. Developmental priorities should change as the chicks begin to independently thermoregulate at around 15 days old, so we expect a transition in chick positions at this time. Chicks consistently in the preferred position should have a higher likelihood of weight gain and fledging. These findings will further our understanding of the key factors and challenges in fledging and reproductive success at our study colony at Punta Tombo, Argentina.

Active nests at the world’s largest Magellanic penguin (Spheniscus magellanicus) colony at Punta Tombo, Argentina have declined 40% since 1987. Climate change has increased rainfall and intense storms resulting in high chick mortality. Although these large-scale weather changes are known to factor into the decline, the effect of weather patterns on the scale of individual days is uncertain. To gain insight into penguins’ daily foraging patterns throughout the annual breeding season, automatic tread scales were placed on a penguin “highway” so when a penguin crossed we could document their time and direction of crossing, weight, and RFID tag. We sought to redesign the scales to improve energy efficiency by switching to solar power and increase accuracy and durability by changing the protective covers on the devices. Most importantly, the modified scales were required to be waterproof to protect internal components from heavy rain and flooding. The batteries used to power the scales had to last 7 days before needing to be replaced. Lastly, the materials used had to withstand temperature fluctuations and be animal-proof. The new design implements solar panels to charge batteries for the scales and cable glands to prevent water ingress through sides of the scales. The updated scales are made of wood and fiberglass then encased in heat-sealable fabric and sealant for waterproofing. Prototypes were firstly tested in the lab to see if they resisted flood-like conditions. Next, we tested whether the scales performed well after being exposed to large temperature changes using temperature controlled rooms. Additional tests were performed in the field to determine whether the design modifications decreased the amount of water ingress and increased battery life. Long-term tests in the field will be important to see how the materials weather over time when faced with temperature fluctuations, flooding, and animal usage.