By Harrison Spilar, Field and Outreach Technician – Ontario Piping Plover and Urban Programs
Do you consider yourself well traveled? We’re willing to bet the average Red Knot has you beat!
The Red Knot is a medium sized shorebird which breeds high up in the Arctic Tundra, and winters as far south as Tierra del Fuego, the southernmost part of Argentina.
There are three subspecies of Red Knot in Canada. Each subspecies has a different categorization as a Species At Risk, according to a 2020 COSEWIC assessment:
- Rufa, which is endangered,
- Roselaari, which is threatened, and
- Islandica, which is listed as special concern.
All populations of Red Knot have seen significant declines, but most notably, the Rufa subspecies. In some populations, they have declined over 80% since the 1980’s.
Red Knots. Photo: Amie MacDonald.
The latest Warblers Podcast episode is honoring these well traveled birds with a deeper look into the Rufa subspecies. Amie MacDonald, the Birds Canada Motus Coordinator and Shorebird Ecologist in Western Canada, tells us there are a variety of factors affecting their populations.
“Red Knots are a really interesting species because they migrate so far. They’re dependent on various habitats and places that are quite far apart. They migrate in these kind of big, multi-day nonstop flights where they burn a lot of energy. And then they arrive at a stopover site, and they spend the next couple of weeks feeding and building up fat reserves to fuel their next big flight,” Amie said in her interview.
This means they are dependent on a variety of different ecosystems across the globe. These different regions are all experiencing negative effects due to climate change, such as increased temperatures, which interferes with the timing of emerging insects for food in their breeding grounds. Red Knots are also threatened by extreme climate events, habitat loss due to coastal development, and rising sea levels.
When Amie says Red Knots travel far, she’s not kidding.
The Rufa subspecies winters in three separate regions:
- Florida and the nearby Caribbean,
- north-central Brazil, and
- southern South America.
Amie MacDonald. Photo: Karl Bardon
Some individuals go as far as southern Argentina, which means traveling as long as 15,000 km per trip, and around 30,000 km annually.
One Red Knot dubbed the “moonbird” lived as long as 19 years. This means that bird travelled around 570,000 km in its lifetime – that’s almost double the distance to the moon!
The Red Knot migration is an event that is carefully timed so they will be able feed on their stopovers throughout their long flight, which leads us to another threat: the horseshoe crab population.
Every year, Red Knots stop in Delaware Bay on the eastern coast of the United States to feed on the horseshoe crabs that spawn on the shore. The Atlantic States Marine Fisheries Commission state that horseshoe crabs provide the backdrop for one of the most interesting marine resource management issues along the Atlantic coast. In addition to their role as a food source for birds, horseshoe crabs provide bait for commercial American eel and conch fisheries along the coast. Their unique blood is also used by the biomedical industry to produce Limulus Amoebocyte Lysate (LAL) (The Atlantic States Marine Fisheries Commission , n.d.). Since horseshoe crab eggs are used in a variety of industries, they are highly sought-after, and often we humans get to the crabs before the Red Knots do.
With climate change, overharvesting of their food sources, and their intensive 30,000 km annual migrations, Red Knots face challenges on every step of their journey. If you see a Red Knot on a favourite beach in Canada, remember: that bird is passing through and still has thousands of kilometers left to travel.
Amie suggests giving all shorebirds space, even those that aren’t breeding, as it allows them to build up the energy they need to continue on their journeys.
For more on these adventurous travelers, listen to the latest Warblers Podcast.
