At this point you can see artificial nesting structures for waterfowl, primarily wood ducks. You may notice these structures in other wooded or water areas along the tour. These nest boxes substitute for natural cavities found only in large old trees. Due to extensive logging of old growth forests, wood ducks were pushed to the edge of extinction in the early 1900s. However, nest box programs like the one here and closely regulated hunting have helped make the wood duck the most common nesting duck in the U.S. east of the Mississippi and Maryland’s most abundant native waterfowl species.
Note the metal cone predator guard below the nest box. Predators, primarily raccoons and snakes, will readily destroy nests without such guards. Natural cavities do not have such protection which partially explains why artificial nesting structures located in good habitat can contribute substantially to production of wood duck nestlings.
Many other bird species such as screech owls and woodpeckers require a tree cavity for nesting but will accept a man-made substitute. Squirrels like them if overhanging branches allow access. On the tour you have also seen nest boxes for bluebirds, tree swallows, and kestrels. The starling and English or house sparrow, both introduced from Europe, have become pests and are aggressive competitors for nest boxes, presenting an ongoing challenge to resource management of our native species.
In late 2004, we helped launch the Maryland Wood Duck Initiative http://dnr.maryland.gov/wildlife/Pages/MWDI/index.aspx by entering into a collaborative agreement to re-develop our wood duck program into one of MWDI’s “best practice” project areas. An inventory of existing boxes, their condition and placement, as well as an estimate of prior hatch results was first obtained. A phased expansion and replacement / relocation of old boxes and predator guards occurred increasing our total box count to 73 from 50. Use of these sites now averages about 70% with a successful hatch occurring in more than 70% of those utilized. Production has grown from an estimated 159 ducklings in 2004 to a range of 450-480 annually with a peak year of 583! More than 4,300 ducklings have fledged over the past 10 years. These gains have been accomplished by minimizing nest strife, reducing starling competition and increasing nesting capacity. Generally by visually hiding and placing more boxes in the woods’ margin (look for boxes along in the woods along the tour) nest dumping and competition with starlings are reduced. Nest use occurs during the March -July period and nest monitoring typically begins in late April through August. Banding of fledged wood ducks periodically occurs in September. Details of our wood duck program can be found on MWDI’s website in the annual public survey report. We appreciate the financial support for the wood duck program which was provided primarily by the Chesapeake Wildlife Exhibition & Sale in memory of Shirley B. Susen.
Ospreys also use artificial structures for nesting. In this marsh, they nest on towers built for observing wood duck nesting as part of our Wildlife Research Project. Since the banning of DDT, which limited many bird populations through thinning of egg shells, ospreys have become common throughout coastal areas of the United States. They prefer nesting over water and will readily adapt to a variety of nest structures.
Our national symbol, the bald eagle, can be seen regularly at this stop. These majestic birds were once endangered, but are now common enough to be removed from the list of endangered and threatened species. Their recovery is symbolic of the effectiveness of modern wildlife management and man’s efforts to provide clean air and water, and to use environmentally safe pesticides. Look for these birds in dead trees both in the marsh and along the back edge of the marsh. Juvenile eagles, which have brown heads and tails rather than the characteristic white, are seen more commonly here than adults.
Continue 0.6 miles.