While working at the Stone
Zoo near Boston, my fellow coworkers and I have grown very fond of a small
flock of ducks the zoo has on exhibit with their Sandhill Cranes.
Two of our "Mystery Ducks"
For a few weeks we weren’t
exactly sure what species of duck they were; they were very small and covered
in light and dark brown plumage. The only thing we were certain of, was that
they were in the diving duck family because they were constantly diving and
searching for food. So, with our
continuing interest in trying to find out what species of duck we were watching,
we started our research.
Since most of us took
ornithology classes in college, it wasn’t hard for us to work together and
break down the steps in identifying wildlife. Since we already knew they were
basically all brown and a part of the diving duck family, we needed to figure
out what species of diving duck inhabited the northeastern part of the United
States.
They were immature Hooded Mergansers - photo by Michaela Henneberg, World Bird Sanctuary Trainer, Stone Zoo, Boston
We only found a few
species that matched the description of the ducks we were observing. These ducks had a very broad crest that
kind of looked like a fan and a serrated bill that was all black. Their crest was so distinctive, we were
able to pinpoint that we were dealing with Hooded Mergansers--the smallest of
the three Merganser species occurring in North America.
Probable male - photo by Michaela Henneberg, World Bird Sanctuary Trainer, Stone Zoo, Boston
After we finally figured
out we were observing Hooded Mergansers, we started noticing that some of the
birds in the flock were starting to change plumage. A few weeks later we
noticed that three of the birds’ eye colors were changing from brown to yellow.
Immature male Hooded Merganser
So, I continued my
research and found that male Hooded Mergansers don’t reach sexual maturity
until their second breeding season.
Once they reach their full adult plumage, the males will have a large
white crest surrounded by black, and their neck and back will turn all
black. Also, their breast and
belly becomes all white and the iris becomes bright yellow, while their feet
become a dull yellow.
Mature male in breeding plumage
Female Hooded Mergansers
remain a grayish brown with a reddish-brown crest, and their upper bill is
black-edged with a mix of orange, while their lower bill is yellow. Unlike the males, the females’ legs and
feet are greenish in color and their iris remains brown.
Probable female - photo by Michaela Henneberg, World Bird Sanctuary Trainer, Stone Zoo, Boston
All in all, we have
determined that three out of the six ducks we have been observing will be males
for next year’s breeding season and they will be a beautiful sight for families
to see.
Submitted by Josh
Kuszmaul, World Bird Sanctuary Stone Zoo Assistant Supervisor
2 comments:
My family visited Stone Zoo on Feb 20, 2014. There were 3 male and 3 female (adult plumage) Hooded Mergansers enjoying the free food & open water in the Crane exhibit. There were also 3 male & 3 female Barrow's Goldeneyes. I assumed at first they were Common Goldeneyes, but they have the white crescent shape on the lores, not round shape. Uncommon birds & fun to watch!
Thanks for the information--it will e interesting to see plumage these six ducklings morph into this coming summer.
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