Lead Shot Ingestion by Mourning Doves and Incidence in Soil

Abstract

Biologists in Tennessee collected 1,949 gizzards from doves harvested on fields managed for public hunting. One percent of the doves had ingested between 1 and 24 lead shot. Preand posthunt soil samples were collected from a field with a history of 8 years of managed public dove shooting. In the top % inch of soil there were 10,890 shot per acre before the September 1 and 2 hunt. The posthunt sample indicated 43,560 shot per acre in the top 3/% inch. For four decades wildlife managers have known that lead poisoning is an important cause of annual mortality to waterfowl. These losses continue to be a management problem (Bellrose 1959, Mississippi Flyway Council 1965, Bagley et al. 1967). Recent cases of lead poisoning in game birds have stimulated interest in spent lead shot as a cause of wildlife mortalities. Locke and Bagley (1967:515) reviewed literature reporting lead poisoning in bobwhite (Colinus virginianus), pheasant (Phasianus colchicus), mourning doves (Zenaidura macroura), and scaled quail (Callipepla squamata). Ingested lead shot was found in bobwhite gizzards being examined for food habits studies in Alabama (C. A. McConnell, personal communication) and Texas (C. J. Barstow, personal communication). Locke and Bagley (1967) also reported the capture of an emaciated immature mourning dove whose gizzard contained two lead shot. The tibia and liver of this bird showed concentrations of lead of 187 ppm and 72 ppm respectively. These authors examined 62 gizzards from hunter-killed doves and in four found 1-3 ingested lead shot. They also found the lead content of 40 dove livers to range from 0.4-14.0 ppm (wet weight). Bagley and Locke (1967), 1 Present address: Oklahoma Cooperative Wildlife Research Unit, Stillwater. 476 studying the concentrations of lead in normal liver tissue of birds, reported a range of 0.4-7.0 ppm for mourning doves. McConnell (1967) studied experimental lead poisoning of quail and mourning doves. Ten percent of the quail and 32 percent of the doves died after being fed lead shot. Some doves died after ingesting between 5 and 35 shot. Others survived when fed as many as 20 lead shot. The increasing popularity of dove hunting and increased public and private dove field management are resulting in concentrations of spent shot which might cause substantial lead poisoning losses of upland game birds. McCartney (1964:185) surveyed the 31 states having an open season on mourning doves. Of these, 18 reported they had dove field management programs of some kind. As Crider (1965:57) pointed out, Since the inclusion, in 1960, of 'normal agricultural plantings' in the hunting methods permitted for migratory birds, public dove hunting programs have rapidly expanded. In 1962, a single large field near Miami, Florida, provided 11,289 doves for approximately 2,400 hunters. Most fields managed by the Florida Game and Fish Commission contain between 125-500 acres. Tennessee has been managing fields for public dove hunting since 1959. These fields are located on wildlife management This content downloaded from 207.46.13.120 on Wed, 14 Sep 2016 05:11:32 UTC All use subject to http://about.jstor.org/terms LEAD SHOT IN MOURNING DOVES * Lewis and Legler 477 areas, often waterfowl areas, adjacent to reservoirs where equipment and personnel are already available to carry out the agricultural operations. The same fields are often hunted year after year, resulting in a buildup in deposits of spent shot, defined as shotgun-fired pellets which fall to the ground after losing their momentum. Brakhage (1966) found up to 122,839 shot per acre in the top 2 inches of soil around shooting blinds at the Duck Creek Wildlife Area in Missouri. Bellrose (1959) reported on a series of nationwide studies of lead shot accumulation on waterfowl hunting areas. The square-foot samples taken in the various studies ranged from 1/2 to 10 inches deep. Accurate comparisons cannot be made but shot accumulations on 24 areas ranged from 0 to 118,048 per