Date of Award:

5-2011

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Committee Chair(s)

John A. Bissonette

Committee

John A. Bissonette

Committee

Jeffrey O. Hall

Committee

Frank P. Howe

Abstract

Lead ingestion adversely affects humans and over 130 species of wildlife. Wild chukars (Alectoris chukar) are documented to ingest lead, but the causes and consequences of this ingestion are poorly understood. The objectives of this research were to 1) examine the influence of habitat use, the hunting season, and seasonal climate on the extent and severity of lead ingestion by chukars in western Utah, 2) assess the effects of habitat use, feeding behaviors, and lead density on the causes of lead-pellet ingestion in captive and wild chukars, and 3) investigate the consequences of lead-pellet ingestion in captive chukars as a function of lead weathering, diet, and wild onion (Allium spp.) supplementation. I documented that 11.5% (n=54) of my sample of wild-harvested chukars contained an ingested lead pellet or increased liver lead (≥ 0.5 ppm). In conjunction with data from captive chukars dosed with lead, I was able to differentiate between bone-lead concentrations resulting from chronic or acute exposure to lead. I documented individuals from seven different mountain ranges with an ingested lead pellet or increased liver lead. I recorded 19 instances of ingested lead during June-October (n=221) and 20 during November-January (n=193). I observed 14 events of increased liver lead for June-October (n=97), but did not find a single occurrence during November-January (n=24). The frequency of lead-pellet ingestion by captive chukars increased significantly when given a greater density of lead pellets with food and when fed a diet with seeds and grit pebbles that were similar visually to lead pellets. I estimated a density of 1,712,134 pellets/Ha in soils at an area used for target shooting. I found significantly more lead pellets in soils near springs than near guzzlers or reference points. I calculated that as many as 58,600 pellets/Ha may be present in soils near springs, and up to 2,445 pellets/Ha in soils surrounding guzzlers and reference points. One #6 lead pellet was able to induce morbidity and mortality in captive chukars. A mixed-seed diet and lead weathering exacerbated the effects of lead ingestion, whereas wild onion supplementation alleviated them.

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This work made publicly available electronically on September 29, 2011.

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