ENVIRONMENT YUKON






 

Birds

Lead surveillance in wild birds

 

Significance

 

The Department of Environment’s Animal Health Unit is determining if there is evidence of lead exposure in Yukon’s wild birds by opportunistically sampling bird livers. Lead poisoning is usually a chronic disease in birds, which is typically detected in birds that are found dead.

Targeted surveillance groups include scavenging birds and waterfowl as they are more likely to ingest sources of lead due to their feeding behaviours:

  • Lead shot and bullets can be ingested by scavengers and waterfowl. Lead shot is no longer used for hunting waterfowl, but lead ammunition is still commonly used for hunting upland birds.
  • Offal piles from hunted animals (i.e., moose, sheep and caribou) often contain lead fragments that can be consumed by scavenger birds.
  • Lead fishing sinkers can be ingested by loons or waterfowl.

 

If lead levels in bird livers remain high or trend upwards, it may indicate that lead shot and bullets, lead fragments and lead fishing sinkers represent a persistent environmental source of contamination.

 

 

 

What is happening?

  • Lead testing is complete for 132 wild birds to date, creating a baseline of information collected since 2013.
  • As more samples are gathered, the data will be analyzed to explore trends based on species, locations and other measures of avian health.

 

Figure 1: Presence of lead and toxicity in sampled wild birds
Source: Environment Yukon

 

Taking action

 

  • The Department of Environment's Animal Health Unit is responsible for health monitoring and diagnosis of disease in both wildlife and domestic animals.
  • By opportunistically monitoring lead levels in target birds, the Animal Health Unit hopes to better understand how birds are being affected by lead and how it varies by species.

 

 

 

Data quality

 

  • Data are collected by opportunistic sampling of the livers of wild birds that have been found dead or euthanized sick birds that could not be rehabilitated.
  • Currently, most samples come from southern Yukon in areas where human population is highest.
  • A laboratory analyzes the samples to determine the concentration of lead in parts per million (ppm) of wet weight detected in each liver sample. These levels determine whether the bird has a normal (up to 0.2 ppm), high-normal (0.2 ppm to 2 ppm) high (2 ppm to 10 ppm), or toxic (more than 10 ppm) lead level.