White-crowned sparrows stop eating ingest small amounts neonicotinoid pesticides. MARGARET ENG Common pesticide makes migrating birds orexic By Elizabeth Pennisi When birds migrate, timing everything. Fly late, miss peak season finding good food, good mate, good nest site. that’s happen migrants unlucky enough eat pesticide-laced seeds, new research shows. Toxicologists studying white-crowned sparrows shown large, grayish sparrows become orexic eating neonicotinoid pesticides, causing them lose weight delay southward journeys.study apply birds well—and help explain dramatic songbird decline recent decades, researchers say. Neonicotinoids world’s widely used class pesticide. They protect seeds—and plants grow them—from insects resistant pesticides. scientists recently found decimate pollinators honey bees bumble bees. Such concerns led European Union ban three compounds 8. Laboratory studies shown neonicotinoids sicken disorient captive birds, data existed affect wild birds, often swoop fields nosh pesticide-laced seeds. Wondering pesticide exposure explain massive recent decline farmland bird species, Margaret Eng, ecotoxicologist University Saskatchewan Saskatoon, Canada, her colleagues got work. SIGN UP FOR OUR DAILY NEWSLETTER Get more great content delivered right you! Email Address The researchers caught dozens white-crowned sparrows (Zonotrichia leucophrys) southern Ontario province Canada birds migrated Arctic southern United States. They kept birds cages food water hours. About dozen received low doses neonicotinoid imidacloprid—equivalent ingest eaten several seeds recently planted field. Another dozen got lower dose pesticide, control birds received same handling pesticide. After hours, Eng tiny radio transmitter each bird’s back released 00,000-square-kilometer site Ontario, regularly spaced radio towers track tagged imals. Within hours, birds highest pesticide dose lost average % body weight % fat stores, key fueling long flights, Eng colleagues report today Science. Over course hours, birds given pesticides stopped eating, taking -third food untreated birds ate, note. Nor birds recover quickly released. Half high-dose birds stuck around Ontario extra . days longer. “It’s few days, know few days significant consequences survival reproduction,” Eng explains. She thinks birds needed extra time pesticide systems, start eat again, regain lost fat. The paper provides “a compelling set observations” shows low doses neonicotinoids affect bird survival reproduction, says Mark Jankowski, toxicologist University Minnesota St. Paul involved work. These effects help explain declines sparrow populations—and apply birds, says Caspar Hallmann, ecologist Radboud University Nijmegen, Netherlands. more work needed prove that, Jankowski adds. Few researchers think United States Canada political ban neonicotinoids despite harms, protective plants. workarounds, says Nicole Michel, population biologist National Audubon Society’s Conservation Science Division Portland, Oregon. For example, rather treat seeds planted, farmers save money reduce birds’ exposure applying pesticide plants insect outbreak occurs. Jankowski says researchers explore methods reduce birds’ exposure, including coming better ways bury seeds—and remove spill—during planting.
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