you're reading...


Mysterious Wintertime Travels of Black Guillemots Revealed in Canada

A Black Guillemot in summer plumage, Atli Harðarson 

The Black Guillemot is a plump little seabird that lives along the Atlantic coast from the Arctic to the Gulf of Maine. Like other open-ocean birds including their cousins, the Puffin and Razorbill, Guillemots are sensitive to environmental changes and can be used as an environmental indicator in marine habitats. It’s important, then, that we understand these birds’ habits and life histories.

Guillemots nest on rocky cliffs and islands during the spring and early summer but it’s unclear where they go during the winter non-breeding period, which takes up most of the year.

Over 2018-2019, researchers from Dalhousie University, the Canadian Wildlife Service, University of New Brunswick, and Acadia University set out to track Black Guillemots as they moved from two breeding islands off the coast of Nova Scotia and New Brunswick to their winter homes, somewhere out to sea. They used a combination of geolocators, positioned in small tags on the birds legs, and stable isotope analysis, or estimates of carbon and nitrogen isotopes in the birds’ feathers, to determine where the Guillemots traveled during the cold months.

Stable isotope analysis is often used where tags may be impractical to use or expected to negatively affect the birds, and give the researchers an understanding of what kinds of food the birds are eating (with carbon isotopes higher in inshore fishes and nitrogen isotopes higher up the food chain). Altogether, the researchers tracked 20 birds from Country Island Nova Scotia and 12 birds from Kent Island New Brunswick, retrieving some of their tagged birds and relying on isotope analysis for the rest.

Country Island and Kent Island Guillemot breeding sites, Baak et. al, 2021

They found that birds from both breeding islands occupied a large but different at-sea area during the non-breeding season. Some Country Island birds remained near their breeding colony on the Scotian Shelf, on the Atlantic side of Nova Scotia, while others moved to the Gulf of St. Lawrence, Bay of Fundy, or Gulf of Maine. Kent Island birds, though, remained in the Bay of Fundy or moved to the Gulf of Maine, indicating that Guillemot populations have different migration strategies.

Black Guillemot migration patterns over the year, Baak et. al., 2021

They also found that some birds dispersed up to ~390km offshore, past the continental shelf break and hundreds of kilometres further than at-sea observations suggested Guillemots traveled. Some Country Island birds traveled to distant locations where they overlapped with birds from Kent Island. Guillemots, like many other seabirds, stick to their own populations during the breeding season to avoid competition. The researchers suggest that in the winter, the birds might share a common prey resource or are following migration routes learned from parents that previously moved between colonies. Atlantic herring, code, sandlace, and other common prey species for Guillemots, are concentrated in the Gulf of Maine and Bay of Fundy, where high tides and vertical mixing ensure greater productivity even in the winter months. This may explain the dramatic travels of some Country Island birds.

Interestingly, birds that remained within just a few hundred kilometres of their breeding colony over winter still showed signs of changing diets throughout the season. Changes from a carbon isotope-dominated diet near shore to a nitrogen-dominated diet off shore might reasonably be expected from birds traveling the long distance from Country Island to the Gulf of Maine, but this change was seen in some birds that stuck around near shore. These birds, the researchers say, must be changing their feeding habits over the year for some reason, from prey species lower on the food chain to those higher up.

The researchers stress that their findings reinforce the importance of areas like the Gulf of Maine and the Bay of Fundy for the many ways these waters support a wide diversity of marine life. These areas are warming faster than many others, and the researchers suggest that ongoing tracking of the two populations would allow us to better predict how seabirds will respond to climate change. In the meantime, we now know more about the mysterious wintertime habits of this northern indicator species and can use that to inform conservation measures for many pelagic seabirds.

BAAK, J.E., LEONARD, M.L., GJERDRUM, C., DODDS, M.D. & RONCONI, R.A. 2021. Non-breeding movements and foraging ecology of the Black Guillemot Cepphus grylle in Atlantic Canada. Marine Ornithology 49: 57–70.


No comments yet.

Post a Comment


  • by oceanbites 3 months ago
    Happy Earth Day! Take some time today to do something for the planet and appreciate the ocean, which covers 71% of the Earth’s surface.  #EarthDay   #OceanAppreciation   #Oceanbites   #CoastalVibes   #CoastalRI 
  • by oceanbites 4 months ago
    Not all outdoor science is fieldwork. Some of the best days in the lab can be setting up experiments, especially when you get to do it outdoors. It’s an exciting mix of problem solving, precision, preparation, and teamwork. Here is
  • by oceanbites 5 months ago
    Being on a research cruise is a unique experience with the open water, 12-hour working shifts, and close quarters, but there are some familiar practices too. Here Diana is filtering seawater to gather chlorophyll for analysis, the same process on
  • by oceanbites 6 months ago
    This week for  #WriterWednesday  on  #oceanbites  we are featuring Hannah Collins  @hannahh_irene  Hannah works with marine suspension feeding bivalves and microplastics, investigating whether ingesting microplastics causes changes to the gut microbial community or gut tissues. She hopes to keep working
  • by oceanbites 6 months ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 7 months ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 8 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 9 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 9 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 10 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 10 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 11 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 11 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 12 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 1 year ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
WP2Social Auto Publish Powered By : XYZScripts.com