A Latin American perspective: the environmental impact of farming wheat and rice treated with carbofuran and Rhodamine B on Brazilian wild birds - Carbofuran and Wildlife Poisoning: Global Perspectives and Forensic Approaches - page 193

50 W 45 W

N

Palmeiras

BRAZIL

Goiás

20 S 20 S

São Paulo

Tarumá

Assis

Cambará

Floraí

Paraná

0 100 Km

50 W 45 W

Figure 7.1 Experiments on rice and wheat plantations were performed in the municipalities of
Assis, Cambará, Floraí and Palmeiras de Goiás. There were large eared-dove ( Zenaida auriculata )
colonial breeding in sugarcane plantations of the Tarumã and Cambará municipalities

Experiments were performed during the planting season, in September 1981, April 1982, and
January, February and October 1983, when numerous bird fl ocks were present. Seven conventional
sowings of wheat or rice seeds treated with carbamates and dyed with Rhodamine B were conducted
in the dry soil plots. The ploughed soil plots were sown once using a tractor-mounted gravity seed
drill in the traditional planting manner (see Figures 7.2a and 7.2b).
Table 7.1 shows the treatments used in experiments 1 to 7, giving the concentration, dosage
and toxicity of the three carbamate compounds applied. Table 7.2 also gives the conditions used
in these experiments, i.e., location, type and quantity of seed used, total area of plot, days of
research, and number and size of individual plots. Figure 7.3 shows the shape and distribution
of plots.
Each plot was searched twice a day for dead birds. The search parties were composed of two,
three or sometimes four people, walking slowly (~3 km/h) or driving in a pick-up truck (~5 km/h).
Searches were undertaken within and around the plots. Bird carcasses were collected and the species
identifi ed. Food present in the digestive tract of each bird carcass was collected from: i) the crop and
oesophagus; ii) the proventriculus; and iii) the gizzard. Any seeds recovered were counted.
In experiments 1 to 7, small (~40 g) and medium-sized birds (~120 g) ingesting seeds often died
within the treated plot. An evaluation of the effect of carbofuran on wild birds was undertaken in
these experiments. The mean, standard deviation and confi dence interval ( 0.05%) of mortality
was calculated, and the confi dence intervals were computed using the student's t distribution.