Mergansers

Back in Week 4, we met the sea ducks, including goldeneyes and the Bufflehead. Mergansers belong to that same group, the tribe Mergini, and the Hooded Merganser wears the family resemblance best.

The Hooded is the only member of its own genus, Lophodytes, which roughly means “crested diver.” It’s often described as a bird in between: it shares many courtship moves and calls with goldeneyes and Bufflehead, and it has even been known to hybridize with Common Goldeneyes. DNA studies still put it on the merganser branch, but you can see the cousins in it.

Look at the male in the photo above. His black-bordered white crest can open like a fan or fold down flat, completely changing the shape of his head. Add a golden eye, chestnut sides, and a black back, and he looks dressed for a party.

The female barely looks like the same species. She’s gray-brown with a bushy cinnamon-brown crest swept back from her head and a slim bill that’s dark on top and yellowish below. Outside breeding season, males can look a lot like her, so check the eye: golden on males, brownish on females.

My best Hooded photos come from Alaksen National Wildlife Area in British Columbia, and I’ve also photographed them closer to home at Jackson Flat Reservoir in Kanab. Of our three mergansers, it’s the smallest and the only one found just in North America.

Hoodeds nest in tree cavities and will also use nest boxes put up for Wood Ducks. Within about a day of hatching, the ducklings climb to the entrance and jump.

Sometimes the female tells you just as much as the male. You just have to know where to look.

The Common and Red-breasted Mergansers are the classic mergansers, genus Mergus: long, low ducks built to chase fish. Look closely at the bill. Its edges are lined with tiny saw-like points that help grip slippery fish, which is why mergansers are nicknamed sawbills. Red-breasted’s species name, serrator, means “sawyer.”

If a merganser reminds you of a grebe, good eye. But back in Week 43, we learned that grebes aren’t ducks at all. Their closest relatives are flamingos. Mergansers and grebes both make a living diving after fish, so they ended up with a similar sleek, low-riding look. That’s convergent evolution: unrelated birds solving the same problem in similar ways.

Honestly, Common and Red-breasted used to blur together for me, especially the females. Here’s what helps.

Start where the head meets the neck. A female Common has a rusty head that meets her white throat in a sharp, clean line, plus a crisp white chin and a thicker bill base. A female Red-breasted looks shaggier, with a spiky crest, a rusty head that blends gradually into gray, and a thinner bill. Young Commons in summer can soften that line, so use more than one clue.

Males are easier. A male Common is mostly white, with a smooth dark green head and a red bill. A male Red-breasted has a shaggy crest, a white collar, a speckled rusty breast, and gray sides.

Habitat helps, too. Commons are birds of fresh water: rivers, lakes, and reservoirs. Red-breasted Mergansers spend winter mostly on salt water along the coasts, so in Utah they’re mainly migrants on big lakes and reservoirs. I’ve spotted them at Jackson Flat Reservoir in Kanab. They’re fast, too. Red-breasted holds the record for fastest duck in level flight, at about 80 mph.

This week, find a merganser and look where the head meets the neck. Sharp line or soft blend? Sometimes one line tells you which bird you’re looking at.