Imidacloprid Poisoning of Songbirds Following a Drench Application of Trees in a Residential Neighborhood in California, USA

In March 2017, 26 American goldfinches (Spinus tristis) were found dead following a drench application of imidacloprid in California (USA). Identical seed fragments were present in the digestive tracts. Imidacloprid was detected in 4 separate pooled samples from 18 birds, in crop/gizzard contents (4.8 ± 1.3 ppm; range 2.2–8.5 ppm) and liver tissues (3.9 ± 0.6 ppm; range 2.1–4.8 ppm). We suspect that fallen elm (Ulmus sp.) seeds were contaminated with imidacloprid during the drench application and subsequently ingested, resulting in acute toxicity and death. Environ Toxicol Chem 2019;38:1724–1727. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.