Lisa holding a Northern Harrier she sampled for her project. This bird was caught, banded, and then released at Hawk Ridge in Duluth, Minnesota.

Lisa Brouellette

Research Q & A

What’s your hometown?

Minnetonka, Minnesota

What are you currently working on?

I am currently working on developing molecular methods to study the diet of migrating raptors.

How are you working toward that goal?

I am using DNA metabarcoding to identify prey DNA from cloacal swabs collected from several species of raptors. I collected about 300 cloacal swabs during fall migration in 2019. Currently, I am working to extract and amplify the DNA on the swabs, which will then be sequenced using high-throughput sequencing.

Why are you focusing your work in that area?

Raptors are very important members of ecosystems. As top predators, they help keep prey populations in check and they are often referred to as umbrella species, since their conservation helps to protect many other species in their ecosystem. Very few studies have specifically looked at the diet of raptors during migration. Migratory diet may differ from breeding season diet due to differences in prey availability and habitat between breeding grounds and migration flyways. In addition to answering questions about natural history, studying diet has important implications in conservation biology. Dietary studies can be used to make informed decisions about land management, to plan for climate change, and to study ecotoxicology.

DNA metabarcoding is a powerful new tool that has been used to study diet in many different species of animals from fecal samples. Raptors, however, are difficult to obtain fecal samples from since extended holding times after capture put them at a higher risk of stress injury. Cloacal swabbing has the potential to significantly reduce handling time of captured birds, making DNA sampling easier, and allowing a greater variety of bird species to be studied.

Where are you working on research/field work?

I collected my samples at Hawk Ridge in Duluth, Minnesota. I am working at the EPA laboratory in Cincinnati, Ohio, to process these samples.

What will your next steps/research be?

Once the DNA from the swabs has been sequenced, I will be able to evaluate the effectiveness of cloacal swabbing. If cloacal swabbing works as a method of studying diet in raptors, I want to use this method to ask questions such as:
1) Are certain diets associated with higher levels of contaminants such as mercury or PFAS?
2) Are there differences in diet within a species, such as differences between males and females or juveniles and adults?
3) Does diet within a species vary throughout the fall migration?

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