Birds rodenticides

One study conducted in Britain between 1983 and 1989 was of barn owls found dead in the field 10% of the sample of 145 birds contained anticoagulant rodenticide residues in their livers, and difenacoum and brodifacoum were prominent among them (Newton et al. 1990). In another study, barn owls were fed rats that had been dosed with flocoumafen. It was found that a substantial proportion of the rodenticide ingested by owls was eliminated in pellets (Eadsforth et al. 1991). The authors suggest that exposure of owls to rodenticides in the field may be monitored by analysis of pellets dropped at roosts or regular perching places. 

Newton et al. (1990) fed mice containing brodifacoum to bam owls, and estimated that birds lethaUy poisoned by the rodenticide n = 4) had consumed 0.150-0.182 mg/kg of the compound. The birds died within 6-17 days of receiving a single dose... 

As discussed earlier, a problem with these field incidents is that the low levels of rodenticides found in many of the poisoned birds are of similar magnitude to those in birds surviving exposure. A low residue level may signify everything or nothing. Additional evidence is needed to establish that the concentrations of rodenticide present in the livers of birds or mammals found in the field are sufficient to have caused death, for example, the presence of hemorrhaging in the carcasses. 

Fergusson, D. (1994). The effects of 4-hydroxycoumarin Anticoagulant Rodenticides on Birds and the Development of Techniques for Non-destructively Monitoring Their Ecological Effects, Ph.D. Thesis, University of Reading, UK. 

Endrin was introduced in the United States in 1951 as an avicide, rodenticide and insecticide. Its principal use to control the cotton bollworm and tobacco budworm peaked in the early 1970s. In 1979, the EPA canceled some uses of endrin and indicated its intent to cancel all uses of endrin (EPA 1979f USDA 1995). By 1986, all uses were voluntarily canceled (Bishop 1984, 1985, 1986 EPA 1993e USDA 1995), except for its use as a toxicant on bird perches, which was canceled in 1991 (USDA 1995). Endrin also was a contaminant in dieldrin (Verschueren 1983) however, all uses of this pesticide have been canceled since the mid-1980s (EPA 1992b). Consequently, there are no longer any significant releases of endrin to the environment in the United States. 

As reviewed by Ujvary some of the earliest natural product-based pesticides were those for the elimination of vertebrate pests. For example, strychnine (Fig. 19), obtained from seeds of Strychnos nux-vomica, is a rodenticide that is an antagonist to the neurotransmitter glycine and is used against a few mammal species, as well as pest birds and fish. The first generation of anticoagulant rodenticides were based on dicoumarin. 

However, a hner level of detail may be reqnired in some sitnations. For example, predatory birds feeding on rodents in an area partly treated with rodenticides may enconnter a bimodal distribntion of residnes in their prey, snch that most prey contain no residnes bnt others contain a lethal dose for the predator. If the unit of analysis were dehned as a whole day s foraging, with residues being averaged over all available prey items, the model might indicate that all the predators experience a snblethal exposnre. In reality, most predators would experience zero exposure, but those that ate a contaminated prey item would die a significantly different result. Therefore, the unit of analysis in this case should be individual foraging events for individual predators. 

Safer and more effective rodenticides and bird repellants... 

The commercial applications of thallium are limited, and at present there are no bulk consumers. Consumption of thallium in the United States has fallen steadily from 1.4 tons in 1987 to 0.3 tons in 1998. Previously, though, over a period from 1920 to 1970, several tons of thallium were used each year in the form of insecticides and rodenticides. However, many countries have terminated its use because of accidental or secondary poisoning of wild animals and birds even children have been known to be severely poisoned as a result of ingesting thallium-containing bait. 

The chemicals used to control vertebrate pests include rodenticides, pis-cicides (fish), avicides (birds), and predacides (predators). 

Yellow phosphorus is a highly toxic element that is still used as a rodenticide. Poultry and wild birds can be intoxicated by consumption of bait intended for rodents. Firework fragments also are a common source of poisoning in free-ranging birds. Affected birds are depressed and anorectic, have increased water consumption, and manifest diarrhea, ataxia, paralysis, coma, and death. 

In addition to the metal yellow phosphorus being used as a rodenticide, other rodenticides are potentially toxic to poultry and other birds. The clinical signs caused by these rodenticides in birds are similar to those observed in other animals. 

Of special interest are secondary intoxications due to free-ranging birds consuming carrions of animals that died of rodenticide poisoning. Strychnine and sodium monofluoroacetate are other rodent control compounds that are involved because they cause acute death in the primary victims and are thus present in high concentrations in carrions. 

Warfarin is used as a rodenticide. Rats exposed chronically to warfarin develop bleeding and death over time. Birds are relatively resistant to the effects of warfarin. Leghorns exposed over 15 days developed no signs of toxic effects. Some birds need to eat half their body weight with feed containing 0.1%... 

Rodenticide kills rodents Miticide kills mites Avicide kills birds Piscicide controls fish Fungicide, kills fungi Slimicide controls slime Algicide kills algae... 

A series of species-specific pesticides avicides (birds), bactericides (bacteria), molluscicides (molluscs), nematicides (nematodes), pisci-cides (fish), rodenticides (rodents), and viricides (viruses). 

Figure 5.1 Example of the discrimination of different modes of action based on tests featuring different targets. The toxicity profiles of herbicidal (H 1-5), insecticidal (11-5) and rodenticidal (R 1 ) compounds with regard to fish, Daphnia, algae, bird and rat revealed highly specific for each of the toxicant classes and can be clearly separated by their scores in a principal component analysis (Nendza and Wenzel, 1993).

Crop losses due to birds, rodents, and slugs. Despite some attention to rodenticides (where resistance is a serious problem), these are under-researched areas of considerable importance. Problems include achieving adequate safety to other mammals, and the necessity to repel but not kill birds. 

In 1978, the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) of 1947 was amended to give EPA authority to control pollution from DDT, mercury, aldrin, toxaphene, parathion and related chemicals. About 1 billion pounds of pesticides, fungicides, and rodenticides are used every year in the United States. While they contribute enormously to the success of agriculture, they can be harmful to animals, birds and hiunans if not used properly. 

Waterways and flood areas can be contaminated with pesticides, especially insecticides, and result in bird deaths (Hxmt et al., 1995 Elliott et al., 1996). Granules of carbofuran in flooded fields have been incriminated as the cause of duck deaths and the cause of death in raptors scavenging dead or debilitated ducks. Illegal use of insecticides resulting in the death of wildlife has also been reported (Allen et al., 1996). Rodenticides have been used to control unwanted rodents and caused collateral deaths (Ruder et al., 2011). The toxicology of pesticides has recently been reviewed (Poppenga, 2012 Gupta, 2012). 

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