Table 1.
Logical structure of the method used to estimate the rate of population decline of the oriental white-backed vultures in India.
Figure 1.
Locations of sites studied in India.
Sites from which liver samples were obtained from carcasses of domesticated ungulates in 2004–2005 for diclofenac assays are shown by circles (n = 67) and centroids of 73 road transect surveys used to measure the population trend of the oriental white-backed vulture in 2000–2003 are shown by stars.
Figure 2.
Cumulative distribution of diclofenac concentrations in liver samples.
The stepped line shows the observed cumulative distribution of concentrations for 1,848 liver samples. Also shown is the fitted cumulative log-normal distribution in which the mean of loge-transformed values is −1.1522 and standard deviation is 1.7670 (thick curve). The thin curve is the fitted third order complementary log-log model in which the cumulative probability is 0.8765+0.1235 (1–exp(-exp(0.3184+0.5415 loge(dliver)+0.05110 (loge (dliver))2+0.005058 (loge(dliver))3)).
Table 2.
Performance of models of the distribution of diclofenac concentrations measured in samples of liver tissue.
Figure 3.
Relationship of diclofenac concentration in selected tissues to that in liver from the same ungulate.
Log-log plots are shown of the concentration of diclofenac in intestine, fat, kidney and muscle against that in the liver. Symbols denote ungulate species and data source: open diamonds-Bos indicus, Experiment 1 [9]; circles-Bos indicus, Indian carcass dumps; squares-Bos taurus, Experiment 2; triangles-Bos taurus, Experiment 3; grey diamond–Bubalus bubalis, [5]. Lines show results from the fitted Model E, in which the geometric mean concentration in the selected tissue is assumed to be a fixed proportion of the concentration in liver (k = 1, see text).
Table 3.
Comparison of five models of the relationship between diclofenac concentration in a specified tissue and the concentration in liver from the same animal.
Table 4.
Arithmetic mean concentration of diclofenac in tissues, as a proportion of that in liver from the same animal a' (see text).
Figure 4.
Relationship between the proportion of oriental white-backed vultures treated experimentally with diclofenac that died and the dose of diclofenac administered per unit vulture body weight.
Plotted points are proportions killed for each of five bins of dose, with 95% exact binomial confidence limits (vertical lines). Bins include 6, 4, 2, 10, and 2 birds respectively (ranked from lowest to highest dose). The thick curve is the fitted probit model relating mortality rate to log dose. Thin curves show the envelope enclosing the central 9,500 of 10,000 Monte Carlo replicate values. The upper panel shows results of analysis of all data. The lower panel excludes the datum for an outlier (vulture Gb11) from the lowest dose bin, which died even though it apparently received an extremely low dose of diclofenac. Data are from Table 2 of Oaks et al. [5].
Table 5.
Estimates of death rate per meal C of oriental white-backed vultures, the annual rate of decline of the vulture population and the percentage of excess vulture mortality that is attributable to diclofenac poisoning E, based upon concentrations of diclofenac in liver samples taken from ungulate carcasses.