by Jessica Bern
As part of “The Role of Birds on the Farm” series, ag professionals and farmers are learning how to support beneficial birds and discourage pest birds. A recent lesson on insect-eating birds supported by nest boxes and buildings was presented by Robyn Bailey of the Cornell Laboratory of Ornithology and Dr. Melanie Truan of UC-Davis.
Bailey manages a citizen science project called Nest Watch. It uses crowd-sourced nesting data from all over North America to “study ways that we can improve outcomes for nesting birds via small, everyday actions.”
One of the questions addressed in Bailey’s presentation was “Which birds can you attract with a nesting structure and which boxes they will use?” To answer this, we were led to AllAboutBirds.org. Begin by finding what bird you want to attract to your farm, then select the region you live in along with your habitat type. Notably, farm/farmland is not a choice on the list of habitats because there can be many types of vegetation communities on a farm. Therefore, it’s suggested to try “grassland” or “range” for a pasture, “shrubs” for a vineyard or “small forest” for a woodlot.
The result is a list of all the birds that nest in the area and habitat you have chosen, as well as which of those listed species of birds are in decline. You’ll also see suggestions such as the best place to attach the box and at what height, to name a few. As an alternate to a standard box, Bailey mentioned using a shelf box. This type of box has one wall removed and replaced with a shelf/landing. However, if you use this, she warned to be careful not to position the box in an area of food packaging or food prep.
To mitigate any damage to the nest box or the birds themselves, some hazards to avoid when deciding where to mount the box included busy roads, cat territories and areas of high human activity and excessive white noise. She said to keep in mind that when it comes time for fledglings to leave the nest, most do so before they’re truly able fly. Therefore, “if you must put the box near a roadside, face it away from the street to keep the fledglings from flying into the road.” If possible, install predator guards on the box as well. This will assist in keeping out predators such as snakes, raccoons and cats. Cats are newer to this list because they are now outside everywhere – on farms, in cities and in residential neighborhoods.
It’s also beneficial to try and place boxes and nest shelves away from loud noises and artificial lighting, especially light at night. Recent research has shown that noise and light pollution are affecting birds on a global scale.
The last topic Bailey addressed was about birds you might find nesting on or around your outbuildings, shed, garage or barn. She recommended, “If you find a nest in an unusual place, or an area that makes it inconvenient for you, put a shelf in a better spot and try to attract the bird away from where they shouldn’t be.”
Truan, who is also a research associate with the Department of Wildlife, Fish and Conservation Biology, spoke next. She is also the founder and director of the Puta Creek Nest Box Highway. This is the term for the 300 nest boxes put up alongside Puta Creek, a local watershed near UC-Davis. The impetus for this project was a noted “lack of cavity nesting birds, primarily secondary cavity nesters … birds that rely on other birds or natural processes to create cavities for them.” The boxes were located near different types of habitats such as grasslands and orchards. The result was 50,000 birds utilizing the boxes, which then produced over 15,000 fledglings.
When deciding what kind of nest box to use, Truan said, “It’s important to consider if the climate is hot, if there are open areas and how much direct sun the box is going to receive.” Wherever possible, she suggested “to place the box under tree canopies or in places where there might be afternoon shade on the east or north … Birds prefer an east-facing entrance hole. If the prevailing winds aren’t too strong, the north side works just as well, but be sure to mount the box securely enough, and in sheltered locations, to withstand the wind which is increasing with climate change.” Another thing to consider if you’re mounting the boxes on trees? Squirrels. They can “take over and chew through the entrance holes, so if you can mount them on poles and fences or on buildings … you’ll probably have a little more luck than if you put them directly on the tree trunks.”
If you have no other choice than to place the box in a spot similar to one for row crops or other areas that don’t have tree canopies, Truan suggested painting your boxes using white non-toxic paint. “This will substantially cut down on the amount of heat that the box absorbs during the day,” she said. Another alternative would be to use heat shields.
Keeping the boxes away from areas where there are herbicides and pesticides is obvious, but it’s also important to keep them away from sprinklers. If they shoot too high, the water can seep in through the entrance holes. In addition, if you can install the boxes in autumn or early winter, prior to breeding season, it gives the birds a chance to find them and get comfortable.