Written by Dr. Eric Wagner
Starting the season – stake survey and tag hunting
In late October, Dr. Eric Wagner and Abrahms graduate student Meredith Honig traveled to Argentina to start the 2025-2026 field season. After getting a provisional permit from the provincial authorities, they arrived at Punta Tombo on October 29. They then spent the next two days completing the annual stake survey, which lets us estimate the number of active nests in the colony. Unfortunately, the number of active nests at Punta Tombo has declined by about 60% since 1987.
After completing the survey, Eric and Meredith began to search for marked penguins in the different study areas and measure their clutches of two eggs. Starting a season in late October means that, in a typical year, almost all the eggs will have already been laid. This year, though, they found that some females were still laying their second eggs. They also found one egg that was one of the longest the project has ever seen, at 9.16 cm in length!
In addition to measuring eggs, Eric and Meredith searched for the twenty geolocator / time-depth (GLD) tags that Eric had deployed the previous March on a trip with Pearl Wellington. This tagging project was made possible thanks to generous support from the Zoo Augsburg and the Nashville Zoo. They attached the tags to penguins with a modified ankle band before they left the colony for their annual non-breeding migration, which can take them as far north as Brazil. Eric and Pearl had deployed GLD tags on ten males and ten females. As of Thursday November 20, 17 of the GLDs had been collected–all ten males, and seven of the ten females.
Bryn and Cora arrive
On November 4, technicians Bryn Carter and Cora Werner Lovell arrived. Now four, the team was able to continue many of our long-standing projects. One such project was to put out the weighbridges that let us measure penguin foraging success and arrival patterns. The team also deployed AX3 accelerometer tags to females and males in a subset of pairs as part of a collaborative project with Dr. Horacio de la Iglesia, a professor in the Biology Department. A central element of penguin behavioral ecology that remains largely unexplored is the temporal distribution of behavior throughout the 24-hour day. This organization of behavior sculpts what is known as a 24-hour temporal niche, which optimizes behavioral and physiological outcomes. These outcomes include predator avoidance, social interactions, mating, and energy balance. The AX3s will let us test what behavioral patterns correspond to higher reproductive success.
As always, the team continued to search for nests, measure eggs, and watch for chick in the study areas. The team saw the first chicks in the colony on November 11, and the first chicks in a study nest on November 13–again evidence that this year is likely to be a later one. With the onset of chicks, the team began to deploy AxyTrek GPS / time-depth / accelerometer (GTA) tags to females and males. Data from these tags will be a large part of Meredith’s dissertation research!
What’s next at Punta Tombo
Eric left Punta Tombo on November 17, a couple of days after finding a penguin he had banded as a juvenile back in 2009! Meredith, Bryn, and Cora will stay until December 13. The year promises to be a busy one, and we are all excited to see how the season develops. None of this work would be possible without the generosity of our funders, and we are grateful to the Tortuga Foundation, Zoo Augsburg, the Nashville Zoo, and a host of private donors for their support.
Do you want to contribute to our field worker’s fund? Consider donating to the Ecosystem Sentinels Research Fund.
