The focus of a Wild Farm Alliance webinar was making the most of birds’ diet and foraging strategies. Sage advice came from Wendell Gilgert, director of the Working Lands Program at PRBO Conservation Science, and from Joanne Baumgarten, director of the Wild Farm Alliance.
According to Gilgert, there are many types of birds that can help keep insects from damaging your crops – those that forage on the ground, in the air, through stalking, soaring, flycatching and even foliage gleaning. Each of these birds has a different beak design to assist them in their tasks (filtering, probing, drilling holes, etc.).
“We can look at what the habitat is and conversely what kind of birds we can expect to see on that property. If you don’t have a habitat to draw in birds of your choosing, maybe create an artificial one for those birds, or plant a habitat and hope over time the birds will come,” Gilgert said.
Aside from native habitats, leaving habitats intact, particularly trees that are aging or even dying, can be very beneficial. This is because these types of trees will develop cavities and exfoliating bark that will attract not only birds, but bats that will go down behind the bark to roost at night.
This type of tree also provides a place for summer, particularly for migratory birds.
Addressing the three main categories of birds, Gilgert began with carnivores. Carnivores, such as great blue herons, are voracious pest predators. They take care of moles, mice and gophers in particular. Insectivores eat only insects; birds in the flycatcher and wood warbler families are two examples. Finally, there are omnivores that eat anything, which can be both a blessing and a curse.
“Some of the birds in this category are most beneficial in springtime, but they also may feed on crops later. The western tanager is partial to insects because they use them for brood rearing in the springtime, but can also be a problem with cherries … nectarines and apricots. You make think, ‘Oh it’s just one peck here or one peck there,’ but if the fruit has been used at all by the birds, the damage becomes an economic liability,” Gilgert said.
Other birds can have nest failures due to a lack of insects primarily found on plants. One example Gilgert cited were caterpillars. “This is important because caterpillars of a lot of different insects, such as butterflies and moths, are major food sources, particularly in the fledgling stage … In yards where they contained less than 70% of native plants, chickadees experienced nest failures due to a of lack of insect food.”
Gilgert noted the benefits of getting involved with NRCS EQIP conservation. The benefits include “funding through the NRCS, which helps in establishing management or facilitating practices, including prescribed grazing, riparian forest buffering and windbreaks,” he said.
On the topic of riparian forest buffers, Gilgert said, “We know that if you can get a 30- to 50-foot buffer along the riparian areas with grounds containing low-mid and high-mid level canopies, then you can get an array of birds that can facilitate insect control of cropland associated with those,” he said, adding that the NRCS also has what’s called a Wildlife Structures Practice that pays for raptor perches and nest boxes.
Having both tree and shrub establishment is important for birds that are going to be taking on insects. Fields with at least two trees had over 13 bird species, whereas fields with just weeds or soil roads had only five, said Gilgert.
Baumgarten focused on how to make farms more bird-friendly and resilient based on where and what birds are eating. According to her, there are several types of swallows that prefer to nest in cavities, such as tree swallows or violet-green swallows. The cliff swallow, Baumgarten said, builds nests under the eaves of buildings. “Allowing them to do that will mean more pest control. There are also many insect pests in orchards and birds foraging in trees, so putting those two together we know that white-breasted nuthatches and Nuttall’s woodpeckers help to reduce 35% of codling moths in walnut and apple orchards.”
She noted a study regarding maple forests on the East Coast which looked at how over two years, black-throated blue warblers and other avian predators were taking out experimental caterpillars in amounts anywhere from 13% to 37%.
Although the dark-eyed junco is often thought of as being a ground forager, they also use shrubs and trees. Large flocks of these birds have even been known to help reduce pear psylla in pear orchards. “Nevertheless, the dark-eyed junco does typically forage on the ground, eating beetles and other kinds of insects, so if the ground is covered, they are more likely to come into the farm and help with pest control,” said Baumgarten.
Baumgarten believes the bluebird is a great example of how you can attract a beneficial bird with nest boxes. “The bluebird will forage in the lower canopy, in the vines and on the ground. Studies show they eat sage leafhoppers which are related to the blue-green sharpshooters, which can carry a vector disease that will kill the vines.”
Corvids (crows, ravens, rooks, etc.) forage in trees and on the ground. Starlings have a niche in the farming world, but farmers should still be wary, according to Baumgarten. This is because starlings are non-native. During nesting season, they feed insects to their young, which is beneficial, but at other times of the year, they can also pose as pests.
by Jessica Bern