Friday, April 16, 2004
Biodiversity Corner: Wood Duck
National Wetlands month is not until May but if we got the rain this week that was forecast, we will be well prepared for wetlands month and in the meantime we will have had lovely weather for ducks.
Name: Aix sponsa or wood duck. Other common
names include Carolina duck, squealer, acorn duck, tree duck, and summer
When and where seen: Seen on Saturday, April 10, from the new bridge on Maple Street, looking toward the western part of the Greenough Pond, with the aid of binoculars. If you see a duck that is so alluring you feel compelled to dive into the swampy pond and swim out to meet it, it might be a male wood duck exhibiting the "glorious plumage that is the birthright of its sex." Tom and D'Ann Brownrigg introduced me to such a duck last Saturday and just moments before I might have made the dive, a female wood duck swam into view. She was way ahead of me.
Distinguishing characteristics: The male wood duck has an iridescent green crest and crown, and a dark purple face. He has a white throat and two white marks that extend up from the throat making a white "bridle." His chest is chestnut, his flanks golden, belly white, back and wings dark blue-green, and the eye and bill are red. He is the ultimate paint-by-numbers duck. The female is gray and brown. Her best distinguishing mark is the white teardrop-shape around her eye. Wood ducks have sharp claws adapted for perching. Their wings are broader than those of other ducks, allowing them to make tight turns as they fly between branches of trees.
Nesting: Wood ducks are cavity nesters but are unable
to excavate their own cavity or even enlarge an existing one. This means
that they need old forests where the dead trees are large enough to
accommodate the size of cavity needed, and where large birds like the
pileated woodpecker will have done the necessary excavation. A survey
in Massachusetts in 1945 showed that wood duck populations had declined
to a very low level due to a combination of hunting, forest clearing,
and the devastating hurricane of 1938. The Mass. Division of Fisheries
and Wildlife began a program for building, placing, monitoring, and
maintaining wood duck nest boxes. The program was very successful and
the wood duck population is healthy. Today there are still 1,750 boxes
at 285 sites around the state being checked by the Division. The boxes
in the Greenough Pond are part of this program. In 1998, 57% of the
470 boxes checked in the northeast part of the state, contained wood
duck nests. A rarer cavity nester, the hooded merganser, was also found
to be using the nesting boxes.
The food chain: The wood duck is largely vegetarian, eating aquatic plants, seeds, berries and acorns. It is said to be particularly fond of acorns and will turn over leaves in the woods looking for them. It also eats insects and some aquatic invertebrates. Wood duck nests are vulnerable to raids by raccoons, and young ducklings are snapped up by snapping turtles.
References: H. W. Heusmann, "Hoods on the Woods," Mass Wildlife Journal, issue #4, year 2000; the Patuxent Wildlife Research Center at www.pwrc.usgs.gov/birds/ - this site also has a recording of the call — not like a typical duck quack - the wood frog sounds more like a duck than the wood duck does.
The only requirements for the Biodiversity Corner are that the subject exists in the wild and was seen in Carlisle. National Arbor Day is coming up on April 30. Write up your favorite tree. Send a note to Kay Fairweather at 392 School Street, Carlisle MA 01741 or to firstname.lastname@example.org.
© 2004 The Carlisle Mosquito