Tips for Building and Placing Delta Waterfowl Hen Houses
Location
Delta Waterfowl’s Hen House recommendations are designed for areas with high wetland and mallard pair densities, specifically prairie breeding areas in south central Canada and north central United States.
Construction
The cylinder or tunnel portion of a Hen House is built using a 36” x 84” section of 14-gauge welded-wire fencing. Smaller mesh (1” x 2”) fencing is preferred to prevent loss of grass from the interior and exterior of Hen Houses. Also, nest structures built with smaller mesh are more rigid and retain their shape better. From one end, roll up approximately 36” to form a 10-12” diameter inner cylinder and hog ring in 3-4 places. Spread approximately 2” of flax straw (or equivalent) on the remaining 4’ of fencing and continue to roll tightly. Hog ring the end of fencing to complete the structure. Fill approximately 50% of the hen house interior with grass hay for nesting material. Ducks do not bring their own nesting material. This must be provided for them.
There are several types of posts/mounting brackets that work well for Hen Houses. The design endorsed by Delta Waterfowl is durable and has many advantages (easy to install and maintain, adjustable height), but does require some minor welding. The images here show a basic example of a Hen House. The cradle is fabricated by welding 2 pieces of 1¼” square tubing into a T. Rounded pieces of ¼” steel rod are welded to the top of the T to form a cradle. The T is inserted into a base post, an 8-10 ft length of 1½” square tubing, and the hen house is wired onto the cradle.
Hen houses with one cylinder per post are preferred because they have higher nest success and were found to be more cost effective than the two cylinders per post design.
Installation
Wetland Selection
Semi-permanent or permanent wetlands are the best locations for Hen Houses as they provide duckling habitat except during extreme droughts. Knowledge of historical wetland water levels and patterns of emergent vegetation is useful, including aerial photos from previous years of drought and high water. Avoid newly restored wetlands, as it will take several years for water depth and patterns of emergent vegetation to normalize. Also avoid rivers, ditches, and portions of wetlands that have significant flow or changes in depth. If water levels fluctuate 3 to 5 feet each year, hen houses will likely be damaged.
Small wetlands are very good locations for Hen Houses, because these wetlands are typically shallower and Hen House damage by ice and wind is usually minimal. Large, shallow wetlands (>10 acres) with small coves and/or pockets of open water within emergent vegetation are also excellent locations for hen houses.
For unknown reasons, Hen Houses simply work in some regions and wetlands and do not in others. To maximize duck production, try a few structures in a variety of locations to see where they work best. Sometimes it may take 3 to 4 years for hens to begin using Hen Houses, so give them plenty of time. Also, keep maintenance in mind when selecting wetlands, as Hen Houses will need to be visited every year. Roadside wetlands are great locations for Hen Houses. Mallards readily nest in roadside hen houses and they are easy to access for maintenance.
Placement
The three aerial images below are examples of initial placement strategies for small wetlands, hemi-marshes, and large wetlands, respectively. Install Hen Houses in open water within 3 to 5 feet of emergent vegetation. Hen Houses can be installed at any time of year, but it is usually easiest in winter when you can walk or snowmobile safely on the ice (>4” thick). In spring and summer, a stable boat or chest waders will come in handy. Drill a hole in the ice and drive the base pipe greater than 2 feet into the wetland substrate. Assemble your mounting bracket, making sure the bottom of the hen house will be 2 to 4 feet above the surface of the water. To minimize loss of nest material, orient the cylinder so that the openings are SW and NE, or perpendicular to prevailing winds. Fill the cylinder half-full with nesting material, but make sure it is possible to see from one end to the other.
Maintenance
Hen Houses should be checked every year to determine usage rates, clean out old nest remains (e.g., eggshells, down, non-hatched eggs), and ensure there is adequate nest material for the upcoming nesting season. In northern portions of the mallard breeding range, late winter (February) is typically best because wetland ice is usually safe for travel and nest material will be fresh when nesting hens arrive in March and April. If time and access allow, revisit Hen Houses after ice-out to repair, reposition, and/or replace damaged or missing structures.
Potential Hen House locations (small wetlands)
Small wetlands (potholes) are great locations for Delta Waterfowl Hen Houses because ice movement and damage are much less likely to occur. Initially install two Hen Houses per wetland.
Potential Hen House locations (hemi-marshes)
In hemi-marshes, small coves and pockets of vegetation provide good wind and ice protection for structures. There are typically more pairs of breeding mallards in a large wetland, so monitor occupancy rates to determine if more Hen Houses are needed.
Potential Hen House locations (open wetlands)
In large open wetlands, place Hen Houses in protected coves, especially those on the upwind side of wetlands where ice and wind damage will be minimized. In the prairies, this is typically the west side of wetlands because prevailing winds are from the northwest, west, or southwest.
Useful Hen House research publications
- Artmann, M. J., I. J. Ball, and T. W. Arnold. 2001. Influence of perennial upland cover on occupancy of nesting structures by mallards in northeastern North Dakota. Wildlife Society Bulletin 29:232-238.
- Chouinard, M. D., R. M. Kaminski, P. D. Gerard, and S. J. Dinsmore. 2005. Experimental evaluation of duck nesting structures in Prairie Parkland Canada. Wildlife Society Bulletin 33:1321-1329.
- Eskowich, K., D. McKinnon, G. Brewster, and K. Belcher. 1998. Preference and use of nest baskets and nest tunnels by mallards in the parkland of Saskatchewan. Wildlife Society Bulletin 26:881-885.
- Zicus, M.C, D.P. Rave, J.R. Fieberg. 2006. Cost-effectiveness of single- versus double-cylinder over-water nest structures. Wildlife Society Bulletin 34:647-655.
- Zicus, M. C., D. P. Rave, A. Das, M. R. Riggs, and M. L. Buitenwerf. 2006. Influence of land use on mallard nest-structure occupancy. Journal of Wildlife Management 70:1325-1333.