When was the last time you played Duck Duck Goose?
Here in the park district’s naturalist office, it’s getting to be a regular occurrence. Only instead of the game’s traditional version, we’ve been playing it via phone and email: “Duck eggs in a garden,” said one caller. “Duck eggs by a school,” said another. “Goose in a flowerbox,” read an email.
Duck messages have been outnumbering goose calls roughly 2:1, so let’s focus on them. The duck callers have been reporting finding duck eggs in all kinds of odd places. So far my favorite has been a backyard fire pit. (Flame-broiled duck, anyone?) But this column is about ducks, not me. What’s up with our wacky waterfowl?
Well, first of all, it’s spring, and spring means nesting season.
Second, though we tend to think of ducks as creatures of water and wetlands, the birds themselves tend to act otherwise—especially in the mallard-rich TriCities. With so many ducks, prime nesting sites are few; hence we frequently find ducks scouting nesting locations a mile or more away from the nearest pond or stream. The areas we tend to think of as atypical nesting grounds—flowerbeds, schoolyards, juniper bushes—become more attractive to female ducks that are in a family way.
Where this behavior runs a-fowl is in the way that mom mallards go about preparing for said family. They don’t just build a nest, lay a bunch of eggs, then sit on them until they hatch, all in one fell swoop. Instead, egg laying and nest building occur gradually, over a course of up to two weeks, and incubation doesn’t begin until the last egg has been laid.
This approach leaves lots of time for well-meaning humans to discover the eggs and then worry about what’s best for them. It also leaves lots of time for nest predators like raccoons and coyotes to help themselves to an egg breakfast, lunch or dinner.
During this time mom duck might also decide that her first nest site wasn’t suitable. Maybe there was too much human traffic, or noise. So she may abandon that nest and start over somewhere else. She might also run into trouble herself. Those same raccoons and coyotes who help themselves to eggs also have a taste for duck.
However, research indicates that a nesting success rate of just 11.5%–a little over one in 10 nests hatching successfully—is enough to sustain a mallard population. I don’t know what the nesting success rate is for mallard ducks in Kane County but, even though it seems like there are a lot of vulnerable nests out there, we still seem to have plenty of ducks along the river and in our neighborhood parks. (Anyone up for a mallard nesting study?)
Although her methods may seem odd, what mom mallard is aiming for is hatch synchronization—that is, having all of her brood hatch within hours of each other. What’s really neat is that the ducklings help this process along. They communicate with each other from inside their respective eggs via clicks as hatching time draws near and emerge at close to the same time—even though the eggs may have been laid weeks apart.
Once out of the egg, baby ducks are precocial—that is, they are covered with down and able to walk and feed themselves. Which is exactly what is needed, when you consider the journey mom duck must take them on once hatching is complete. Because she doesn’t want to spend long sitting in a nest on the ground, surrounded by 12 or more young, she hits the road with her brood in line behind her, intent on reaching her home body of water a.s.a.p.
(Most waterfowl follow this strategy of synchronization, while many other bird species hatch their young asynchronously. Take owls, for instance. Mom owl begins incubating her first egg the moment it is laid, so that individual will hatch more quickly than an egg laid a few days later. No. 1 owlet has an advantage in that it will be the largest of the brood, and perhaps the only one to survive if food is in short supply.)
If, over the next few weeks, you find a collection of bluish- or greenish-white eggs, just slightly larger than chicken eggs, on the ground, try your hardest to squelch your natural tendency to gather them up and “save” them. Chances are, mom duck will be along shortly to tend to their needs.
There’s a phrase that’s commonly used in wildlife rehabilitation. It’s meant to apply to baby animals, but is equally apt for eggs, too. Try to make it your motto this spring: “If you care, leave them there.”
Pam Otto is the manager of nature programs and interpretive services for the St. Charles Park District. She can be reached at potto@stcparks.org or 630-513-4346.