Waves crash against the hull of a small boat as it approaches Seal Island. It passes over shoals riddled with shipwrecks from over the centuries, but it’s not the history that lures this boat closer to shore; its crew is here to study the wildlife that have come to reside on the island. Hauling equipment from the boat onto the rocky banks, Amanda Rosa Giovinazzo, a graduate student from the University of New Brunswick in seabird ecology, accompanies Nature Trust team members including Stewardship Coordinator Liv Monck-Whipp and Senior Conservation Scientist Dominic Henry. Seal Island is a significant stopover site for migratory birds along the Atlantic flyway.

This field visit is part of a long-term project to understand the effect of invasive species (particularly rats and Snowshoe Hares) on bird populations and learn how removal of invasive species might impact the remaining ecosystem on the island.

Amanda is helping to build the baseline for an invasive removal feasibility study in partnership with an organization called Island Conservation, as well as the Canadian Wildlife Service and the Nova Scotia Department of Natural Resources. Wes Jolley and Julie Sullivan from the Island Conservation Team are also here to learn more about this place, as well as Amanda’s supervisor, Dr. Heather Major. Amanda’s work will help the team gain a stronger scientific understanding of the island’s ecosystem and what the implications of invasive species removal might be.

Her research is following three main steps:

First, she is identifying the vertebrates (mammals and birds) present on the island. To categorize species presence, data were already collected by the Canadian Wildlife Service and the Nova Scotia Department of Natural Resources. They deployed passive acoustic recording units (ARUs) across the island, which continuously record bird and bat calls. Additionally, they collected eDNA water samples and set up camera traps, which show that the only native mammals on the island are bats (likely migratory) and Masked Shrews.

Amanda is now analyzing the ARU recordings using BirdNET, an automated sound detection program. She is reviewing data from four acoustic recording units, analyzing approximately eight hours per day, with a focus on sunrise, sunset, and nighttime over the entire year of 2025. For reference, the 28 day breeding season alone, is roughly 930 hours of audio! Luckily, there are tools like BirdNET to assist in analyzing large amounts of data. Continuous recordings have been collected since 2023 and are still being collected, forming a long-term acoustic archive for Seal Island.

Next, Amanda determines the pathways of interactions by constructing a food web to understand how they interact, their diet, and particularly how invasive vertebrates affect native species. The primary invasive species on Seal Island are Norway Rats and Snowshoe Hares, the former introduced by accident and the latter introduced by people for hunting. Introduced Muskrats, House Mice and Red Squirrels are also present. Like many islands worldwide, Seal Island once had feral cats, which preyed on nesting seabirds and contributed to population declines. Although the cats have been removed, Norway Rats continue to prey on bird eggs and hares continue to eat the vegetation on the island, to the point that they are preventing forest regeneration.

Finally, using this ecological framework, Amanda will model different scenarios to see the interdependence of species on Seal Island to help predict how the ecosystem might respond to changes in mammal species on the island. Understanding how these species interact is essential to avoid unintended consequences such as “mesopredator release.” This phenomenon occurs when the removal of one predator, such as cats, allows another, like rats, to increase in number. Amanda’s modeling will examine whether removing certain invasive species (such as rats) could inadvertently boost populations of others, such as Red Squirrels or mice, potentially worsening impacts on seabirds. The model’s output will estimate how likely each species is to be positively, negatively, or neutrally affected under various scenarios.

Currently, Amanda is at the first step in her research: processing audio recordings. She begins with the recordings of birds during the breeding season, because invasive species, particularly rats, primarily affect nesting seabirds (and other birds) by consuming their eggs. As a result, seabird numbers on Seal Island have declined. Amanda’s goal is to determine which seabird or breeding bird species are still present during this critical time. She is especially interested in finding any remnant populations of species that once nested on the island but are no longer as common, such as Atlantic Puffin, Leach’s Storm-Petrel, Black Guillemot, or Bicknell’s Thrush. If Amanda detects species such as Leach’s Storm-Petrels or other seabirds, it could indicate remnant nesting populations either on Seal Island or nearby islands such as Mud Island or Flat Island, which currently host more seabirds. Identifying these remnants is critical: the presence of remnant populations means that if invasive species were no longer a threat to their breeding habitats, then they would likely return and increase bird populations.

Beyond ecology, Amanda has been grateful for the hospitality and knowledge of the human community on Seal Island. In connecting with the local residents through community meetings on the mainland and conversations during multiple field visits, Amanda has learned about bird species, erosion and changes in the ecosystem through the eyes of those who also call it home. She has been overjoyed to find a shared interest in seabirds with community members eager to share their birding observations from the island.

As they watch Seal Island become smaller on the horizon, the crew’s notebooks filled with observations and conversations, Amanda is grateful that this island has been her introduction to the region.She leaves this field visit impressed by the residents’  friendliness and warmth. She’ll now return to the lab at UNB to comb through her field notes while listening intently to recordings to better understand the birds that are on the island.  As her research continues to unfold and build the baseline for the feasibility study, her work will bring Seal Island a step closer to being a safer place for migrating and breeding birds.

The ongoing restoration project on Seal Island involves numerous partners, including Island Conservation, the Canadian Wildlife Service, the Nova Scotia Department of Natural Resources, UNB’s Atlantic Lab for Avian research, and community members of Seal Island. 

If you would like to support Amanda’s research and ongoing efforts to restore Seal Island, please consider donating to the Nature Trust, or get in touch with our giving team.