Experimental Lead Pellet Ingestion In Mourning Doves (Zenaida macroura)

摘要

Because the relationship between lead pellet availability and ingestion by mourning doves (Zenaida macroura) remains uncertain, we conducted an experiment to determine if doves held in captivity freely ingest lead shotgun pellets, investigate the relationship between pellet density and ingestion and monitor physiological impacts of doves ingesting pellets. We conducted two trials of the experiment with <60 doves per trial. We randomly assigned 10 doves to one of six groups per trial; 10, 25, 50, 100,200 pellets mixed with food and a control group with no pellets. We monitored ingestion by examining x-rays of doves 1-d post-treatment and monitored the effects of lead ingestion by measuring heterophil:lymphocyte (H:L) ratios, packed-cell volume (PCV), blood lead, liver lead and kidney lead. Pooled data from both trials showed 6 of 117 (5.1%) doves ingested lead pellets. Two mourning doves ingested multiple lead pellets in each of the treatments containing a mixture of 25, 100 and 200 lead pellets and food. Doves ingesting lead pellets had higher blood lead levels than before treatment (P = 0.031). Post-treatment H:L ratios, however, were not different compared to pre-treatment values (P = 0.109). Although post-treatment PCV decreased for four of six doves ingesting lead pellets, overall they were not lower than their pre-treatment values (P = 0.344). Liver (P < 0.0001) and kidney (P = 0.0012) lead levels for doves ingesting pellets were higher than doves without ingested pellets. Our lead pellet ingestion rates were similar to previously reported ingestion rates from hunter-killed doves and our physiological measurements confirm earlier reports of a rapid and acute lead toxicosis. Similar to previous field research, we did not observe a relationship between pellet density in the food and ad libitum pellet ingestion. Although one approach would be to ban lead shot for mourning dove hunting on managed public hunting areas, further research is necessary to ensure that policy development and implementation have a consensus among stakeholders.