Will mallards use a nesting box?

Mallards are one of the most widespread and recognizable ducks in North America. They are a medium-sized dabbling duck known for their iridescent green heads and white neck rings. As their natural wetland habitats have declined over the past century, interest has grown in providing artificial nesting sites like nest boxes to support mallard breeding. But will mallards actually use nest boxes?

Natural Nesting Habits of Mallards

Mallards naturally nest in cavities near water across their breeding range, which includes most of North America. Favorite nest sites include:

• Tree cavities
• Old woodpecker holes
• Natural hollows in dead trees or stumps
• Dense shrubbery
• Nest tunnels dug into dirt banks
• Thick grassy vegetation
• Nests built on the ground lined with available materials

The female mallard builds the nest and lines it with down feathers plucked from her own breast. She will lay 6-15 pale greenish-white eggs and incubate them for about 28 days while the male remains nearby. Once the ducklings hatch, the female leads them to water where the young feed themselves.

Mallards prefer concealed, quiet nest sites near water. The nest offers protection from predators and shelter from weather. Easy access to water is crucial once the young hatch. Ideal sites also provide overhead cover when entering and exiting the nest so the birds aren’t easily spotted.

Advantages of Artificial Nest Boxes for Mallards

As natural wetlands have been drained and destroyed, mallards have fewer quality nesting sites available to them. Nest boxes can supplement their breeding habitat in some cases. Potential benefits include:

• Providing safe, dry cavity nesting options in areas where natural options are lacking
• Allowing breeding in territories where mallards are present but unsuitable habitat prevents nesting
• Protecting eggs and nesting females from predators
• Giving researchers the ability to more easily monitor mallard breeding biology and behavior

Several studies have investigated mallard use of nest boxes across North America with promising results:

These findings indicate mallards will make use of nest boxes, especially where quality natural sites are limited.

Mallard Nest Box Design Considerations

If you’d like to put up nest boxes to attract mallards, keep these nest box design considerations in mind:

Size

Mallards are medium-large ducks. The nest box should be big enough for the hen to fit comfortably while incubating. Minimum interior dimensions of 12 inches wide x 12 inches deep x 15 inches high are recommended. The entrance hole should be 4-5 inches across.

Placement

Choose sites very close to water, ideally connected by an overhead wire or tube for safe passage. Areas protected from predators and inclement weather work best. Attach boxes on poles in deeper water or fasten to trees. Nest boxes can also be installed on floating platforms. Avoid high disturbance areas. Face the entrance hole towards the water.

Materials

Use durable, weather-resistant, non-toxic materials like exterior plywood painted or stained for camouflage. Some plastic nest boxes are available. Add drainage holes on the bottom with a few wood shavings inside for nesting material.

Protection from Predators & Weather

Include an overhanging roof to shield the entrance from rain. Make sure no perches or footholds are near the box where predators could access it. Consider predator guards to block access to the interior. Monitoring and maintenance will be needed.

When to Install

Put up the nest boxes well before breeding season, which typically runs from March to June depending on latitude. This gives the mallards time to find and acclimate to the new nesting resource.

Tips to Encourage Mallard Use of Nest Boxes

Follow these tips to increase the likelihood that your installed mallard nest boxes will get used:

• Choose sites with maximum safety, shelter, and seclusion
• Group 2-10 boxes together in quality habitat near water
• Keep disturbance and predation risk low through careful box placement
• Line the inside floor with a thin layer of wood shavings for nesting material
• Clean out old nesting material in fall to prepare for next season’s use
• Perform annual maintenance like replacing rotten wood and re-staining
• Monitor and protect boxes during nesting season

Mallards and other ducks can have strong nest site fidelity, returning to the same box year after year. Get your nest boxes up well before breeding season and implement good protective measures to establish a safe nesting area they’ll come back to.

Conclusion

Research shows that mallards will readily use nest boxes, especially in areas where natural nesting sites are scarce. When properly constructed and located, nest boxes can provide quality breeding habitat to support mallard populations. To encourage mallard use, install nest boxes with the right dimensions in ideal protected locations very close to water. Perform regular maintenance and take precautions against weather and predators. With some effort, nest boxes can be an effective conservation measure to boost mallard productivity.