Birds Continued from Page 7
on insects,” Long continued, noting again the exception of crows. Using birds in field crops—particu- larly seed crops—is a learning process that could mean watching birds to un- derstand which are pests, when they’re pests, when to manage them and learn- ing to appreciate when they’re benefi- cial, she said. Seed crops such as sunflowers, for ex- ample, could have birds that are benefi- cial early in the season, such as gold or purple finches that feedon insects to feed their young. Later in the season, those same birds switch to seeds, Long said. “It is a little bit of a learning curve with understanding birds and their biology, but once you get it, birds can provide a huge amount of beneficial pest control services,” she said, adding that providing natural habitat on the farm plays a very significant role in encouragingmore nat- ural enemies, including birds. “When you remove habitat all around the farm, there’s nowhere for this wild- life to go—birds and such—except for on crops. Then you’re more likely to get wildlife and crop-production conflicts with birds feeding on crops,” she said.
UC Davis re- searcher Sacha Heath checks bags of codling moth larvae af- fixed to a walnut tree for signs of predation. A UC study monitored how many lar- vae beneficial birds removed from an orchard.
There is always the fear that habitat will draw in pest birds, but Long said pest birds are present in crops regardless of field-edge habitat. “Large flocking pest birds like starlings, blackbirds and crows seemmost interest-
ed in the crop, or sometimes structures like corrals,” Long said. “We found that if you have hedge- rows, you’re increasing the beneficial bird numbers by tenfold and diversity by fivefold,” she said. “The more we work withMother Nature to encourage natural enemies on farms, themore natural pest control we’ll have.” Long said their research found birds to be beneficial for controlling pests, and that they controlled at least 35% of the codlingmoth pests inwalnuts. If bats are added, along with beneficial insects, she said there would be “pretty good natural control” of the pests. Bat and owl houses represent a good investment, Long said, as the research shows that encouraging these natural enemies really does help to control pests. Using birds becomes even more im- portant with fewer chemicals being reg-
istered in California, she said, noting that in alfalfa, for example, “It’s just re- ally worrisome that there’s just no new insecticides coming down the pipeline for weevil control.” Using birds for pest control for wal- nuts poses minimal food-safety risk, Long said, because of the husk around the walnut shell and the enclosed nut. She said the benefits frompest control by bug-eating birds far outweighs any risks. “Clearly, in this case where we are losing so many insecticides due to re- sistance or due to regulations, we really need to look for ways to control pests naturally. One way is to encourage nat- ural enemies like birds and beneficial insects, and bats even, to come in and help us out,” Long said. (Kathy Coatne y i s a repor t e r in Bend, Oregon. She may be contacted at kacoatney@gmail.com.)
8 Ag Alert September 9, 2020
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