A mystery never fully explained: Where are my wood ducks?

BRAINERD – Last week, a brood of 1-day-old wood duck ducklings — 11 in all — leapt into life from a wood duck nesting box I placed on my acreage located a few miles south of town.

It was gratifying to know I had provided a safe haven for the hen wood duck while she had spent the past 30 days or so incubating her clutch.

But all was not rosy on the Marchel property.

Of the 13 nesting boxes I monitor on my land, the hen wood duck occupied one of only four boxes being used. Two of those boxes were occupied by hooded mergansers, the other by a hen wood duck. Last spring only five of my wood duck nesting boxes were used.

During a typical spring about eight or nine of my boxes are occupied. We all know this spring, weather-wise, was far from typical. My ponds were ice covered into early May. Was that the reason for my lack of occupied nesting boxes? Is the fact that the Minnesota's wood duck bag limit was raised from two birds daily to three starting in 2011 a reason. Or does the fact the duck hunting season in Minnesota has opened a week earlier the past two seasons, resulting in a higher kill of local wood ducks, have an effect on the number of birds returning in the spring?

I realized, of course, two years of limited nesting of wood ducks on my land is no reason to jump to conclusions of any kind. Some research was in order.

My first contact was Roger Strand, of New London, Minn. Strand has placed and maintained wood duck nesting boxes dating to the early 1950s. He is the editor of Newsgram, a publication produced three times per year by the Wood Duck Society. Strand monitors about 100 wood duck nesting boxes in the New London area and is known nationwide as an authority on wood ducks.

His wood duck box occupation rate over the years is about 85 percent, including some used by hooded mergansers.

"That's about where we're at this year," Strand said.

Strand is taking a wait-and-see attitude about whether or not the move to a three wood duck bag limit in 2011 will affect the percentage of nesting boxes that are occupied in spring. He believes the early opening date might be more of a factor, since a portion of local nesting wood ducks vacate the state as soon as the weather cools in September.

"The early opening date definitely results in more local wood ducks in the hunting harvest," Strand said. "But I have not seen a reduction in nesting box use, at least in my area."

Steve Cordts, waterfowl staff specialist for the Minnesota Department of Natural Resources, says the timing of the thaw was very unusual and led to wetland conditions that vary widely across the state. That might account for variable wood duck nesting box use this spring.

"In 2011, the first year we allowed hunters to take three wood ducks daily, the harvest went from around 80,000 wood ducks in years prior, to roughly 150,000, nearly double the pervious years." Cordts, like Strand, believes the early duck opener likely is more of a factor in the higher wood duck harvest than the three bird daily limit.

Cordts added a wood duck harvest of 150,000 in not unprecedented.

"We had wood duck harvest numbers in the 180,000 range during the late '80s and early '90s," said Cordts, who stressed wood duck harvest nationwide is within federal harvest goals, which are set to maintain a sustainable wood duck population.

So, the mystery as to why most of my wood duck boxes stood empty this spring remains unsolved. The rivers, streams, and ponds in the Brainerd area are full to the brim and have been since the thaw. Hopefully, as Cordts noted, that's part of the puzzle.

Regardless, later this summer I plan to move a few of my nesting boxes that, for whatever reason, were not occupied the past two springs.

Bill Marchel, an outdoor writer and photographer, lives near Brainerd.