A concerned Wauchope resident has called FAWNA Wildlife Rescue after dead magpies were found on the Timbertown estate.
The rescue group was asked if it might want the bodies for toxicology reports.
"Unfortunately such laboratory testing is beyond the means of this cash-strapped volunteer group," said FAWNA's president Meredith Ryan.
"Toxicology testing and reports can take many weeks and FAWNA felt it was more important to advise the public what we think might be the cause."
Ms Ryan says it is usual in early autumn for different types of lawn caterpillars to hatch and start munching on lawn grasses, leading householders to reach for the chemical spray bottle to combat the problem.
"Army grubs are one of the most common and are relished by the insect and meat-eating birds. If the grubs are poisoned the toxins can pass through the grubs into the birds that prey on them causing unintended deaths," she said.
FAWNA says there are a number of home made recipes available.
"Products containing the active ingredient Esfenvelerate (a broad-spectrum insecticide toxic to most insects, but less toxic to birds, and of minimal toxicity to mammals) is safer to use than any other pest control product. In addition it also prevents some damage to your foliage," said the FAWNA president.
Ms Ryan says householders love their local birds and we should all try non-toxic methods of control of any form of "pest" in preference to products that can harm our free-living wildlife.
For 24 hour wildlife rescue contact FAWNA on 6581 4141.
FAWNA's next induction training course will be held on July 7 in Wauchope and details are available on www.fawna.org.au