Sources of Curiosity
Questions from April 7 walk
What do Bufflehead ducks eat, and where do they nest?
Bufflehead ducks eat mostly aquatic invertebrates, with seasonal shifts between freshwater insects and marine crustaceans.
Details:
On freshwater (breeding season):
Dragonfly & damselfly larvae
Midge larvae
Mayfly & caddisfly larvae
Water boatmen
Amphipods
Snails and small clams
On saltwater (wintering grounds):
Shrimp
Crabs
Amphipods & isopods
Marine snails & mussels
Occasionally herring eggs, small fish
Buffleheads are cavity nesters, often re-using nest cavities from Norther Flickers or Pileated Woodpeckers.
For more information about Bufflehead ducks, see this article from AllAboutBirds or this from Audobon.
Why do American Eels swim to the Sargasso Sea?
The American Eel is a shape‑shifting traveler that starts life in the middle of the Atlantic Ocean, grows up in our rivers and ponds, and then swims all the way back to the ocean to have babies. It’s one of the most mysterious fish in North America.
1. Born in the Sargasso Sea
All American eels begin life in a warm, floating patch of ocean called the Sargasso Sea.
Tiny eggs hatch into leaf‑shaped babies that drift with the ocean currents.
Think of it like: Starting life on a giant ocean “lazy river.”
2. Leptocephalus: The Ocean Drifters
These baby eels, called leptocephali, are see‑through and shaped like willow leaves.
They don’t swim much — they ride the Gulf Stream toward North America.
This trip takes about one year.
Think of it like: A long, slow road trip where the current is the driver.
3. Glass Eels: The Tiny Ghosts Arrive
As they reach the coast, they transform into glass eels — tiny, clear, fully formed eels.
This is the stage caught in Maine’s elver fishery.
They start swimming into estuaries and rivers.
Think of it like: They finally “wake up” and start exploring on their own.
4. Elvers → Yellow Eels: Growing Up in Maine
Glass eels gain color and become elvers, then yellow eels.
They live in:
Streams
Ponds
Marshes
Big rivers
They eat insects, crayfish, worms, and small fish.
They can stay in Maine waters for 10–30 years.
Think of it like: This is their childhood, teen years, and adulthood — all in our freshwater.
5. Silver Eels: The Final Transformation
When they’re ready to reproduce, yellow eels turn into silver eels:
Silvery sides
Big eyes
Stronger swimming muscles
They stop eating and begin a massive migration back to the Sargasso Sea.
Think of it like: A superhero transformation before their final mission.
6. Spawning and the End of the Journey
Silver eels spawn in the Sargasso Sea.
After spawning, they die, completing the cycle.
Their young drift away to begin the story again.
Think of it like: A full-circle journey — ocean → river → ocean.
For more information, take a peek at these sources: