Our Garbage is Landing in Birds’ Nests

Our garbage is landing in birds’ nests

Our garbage is landing in birds’ nests

By Melina Damian, Professor of Energy, Environment & Sustainable Development at Centennial College and Editorial Assistant at Ontario Nature

Did you know that most garbage in marine and freshwater ecosystems is plastic?

Unfortunately, even if we dispose our waste correctly, there is always a possibility that it will end up in the natural environment. Especially plastics, since they’re so light-weight and can easily be transported via storm water or wind currents. Their chemical composition also makes them incredibly durable. Depending on the type of polymer, they can take hundreds to thousands of years to break down.

Plastics and other human-made debris pollution pose a threat to wildlife due to entanglement and ingestion. Marine turtles, marine mammals and seabirds are the most commonly reported species to be affected by debris pollution. There is limited research on how this problem affects freshwater ecosystems, such as the Great Lakes, but evidence suggests that freshwater birds face the same risks when they interact with human-made debris. One of the most common interactions birds have with human-made items is when they use them for nest building. This poses risks for both adults and juveniles since this interaction occurs in breeding sites. There are many reasons why birds may use human-made debris for nest building. First, some debris resembles organic nesting material or prey color. Second, birds may find them useful when attracting and interacting with mates.

Double-crested cormorant sitting in a nest of plastic
Double-crested cormorant on a nest at Tommy Thompson Park, Toronto, ON (photo credit: G. S. Fraser)

Studying Double-Crested Cormorants

During the fall of 2018, my supervisor Professor Gail Fraser and I decided to explore this issue further. Our study focused on the largest colony of double-crested cormorants in North America, which is located in Tommy Thompson Park, Toronto. We began by examining 50 ground nests and extracted all human-made debris. We then measured, weighed and carefully categorized them in the lab.


Garbage in birds nest
Double-crested cormorant ground nest at Tommy Thompson Park displaying different types of human made debris (photo credit: M. Damian).

In total, we retrieved 1,442 items, weighing a total of 13.81 kg. Most of what we found was plastic, but we also retrieved a lot of metal, electrical wire and various other types of garbage. Sadly, the nest that had the most debris contained 80 pieces.

The Great Canadian Shoreline Cleanup supports volunteer-led initiatives to clean and monitor human-made debris found in Canadian shorelines. Several volunteer-led surveys often take place along Lake Ontario, and five of these were conducted at Tommy Thompson Park between 2011 and 2018. During our study, we also wanted to look at whether our findings and the findings from the volunteer-led surveys were similar. If that were the case, we could argue that double-crested cormorants in Tommy Thompson Park could be considered ecological indicators – indicator species are those that reflect the health condition of the ecosystem they inhabit. However, after a series of statistical analysis we found that the debris present in the nests significantly differed from the debris found by volunteer surveys in the park (even though, both datasets reflected plastics to be the most abundant debris!).

Contributing to Science

Our research findings make an important contribution to science because it helps us understand the threat that anthropogenic debris pollution poses not only to double-crested cormorants, but to other species that live in Tommy Thompson Park. Additionally, sampling cormorant nests every three years was recommended by scientists in 2014 as part of a national strategy to monitor plastic pollution in Canadian freshwater ecosystems.

So next time you use that plastic lid from your coffee cup, think again: do you really need it? What if it ends up in a cormorant nest? There are always sustainable alternatives to plastics, and it’s imperative that we value the importance of our individual choices for the welfare of all animal species!


Malina Damian

Melina Damian is an Environmental Consultant for York Sustainable Enterprise Consultants (YSEC), and as of January 2020 she will start teaching a graduate course on Energy, Environment and Sustainable Development for the International Development Program at Centennial College. She has a Master in Environmental Studies from York University, Toronto, and a graduate diploma in Environmental Education. Melina’s graduate research focused on the impacts of anthropogenic debris pollution in marine and freshwater environments and critical wildlife nesting habitats. Some of the different environmental organizations that she has worked at and volunteered for include Wildlife Preservation Canada, Toronto Wildlife Centre, FoodShare and the Canadian Organization for Tropical Education and Rainforest Conservation (COTERC).

She is also an experienced public speaker, she has delivered two guest lectures at York University, one at Ryerson University and has presented at over nine different conferences and academic events over the past two years. Her main area of expertise in the environmental field are plastic pollution, wildlife conservation and environmental education.