News & Notes

Maine Loon Mortality: 1987-2012

Friday, March 8th, 2013
Posted on:

Loon x-ray showing swallowed lead sinker.

For 25 years volunteers for Maine Audubon have collected loon carcasses found washed up on beaches and shorelines. Over that time these some 450 carcasses have been collected and sent to veterinarians at Tufts University for examination to try to determine the cause of death. The results are compiled in a twenty page report, and they show that lead sinkers and lead-headed jigs are the leading cause of death for Maine’s loons.

  • Lead poisoning has been documented in 27 species of birds in North America, but the rate of ingestion is much higher in common loons compared to other waterbirds.
  • Loons die when they ingest lead objects, either accidentally ingesting them while eating gravel from lake bottoms, or by catching fish with lost or broken lead sinkers and jigs attached.
  • Lead kills adult loons almost exclusively, and death by lead happens within a fairly short time, probably two weeks or less.
  • Of 352 adult loons collected since 1987, 97, or 28%, had died from ingesting lead fishing tackle.
  • Most of the lead objects (58%) examined from loons that died from lead poisoning were lead-headed jigs.  Another 32% were lead sinkers.
  • Jigs likely ranged from one inch to two and a half inches at the time they were ingested.
  • Lead mortality has not changed significantly in the time period before the ban on lead sinkers a half-ounce or less (2002), compared to the time since.

Maine is lucky to have a robust population of 3,000 adults in the southern half of the state, and that number has increased from a low of around 1,500 back in 1987. However, the number of chicks produced each year remains low (never more than 400) and has not increased at all over that time period. 

Every chick matters, and every adult loon lost to lead is a potential parent.

Because of concern over the long-term health of our loon population, Maine Audubon has introduced legislation to expand the current lead sinker ban, and we’ve written a short fact sheet to share the major findings from our recent analysis.

Use this fact sheet to hang on your office bulletin boards, or in meetings [pdf] »

Stay tuned at our advocacy pages for more information about this bill as it moves through the legislative process this month, and what you can do to help.  Letters and phone calls to legislators will be important in passing this critical legislation, and we thank you in advance for any help you can offer!

Receive Action Alerts by Email »