63
food (Best 1995). These birds are unable to distinguish granular form of pesticide
because the carrier medium of pesticide granules is sand (silica) which is the ideal
natural grit material (Mineau 2009). Therefore, particulate forms of pesticide may
enter into the body of avian fauna either through intentional or unintentional ingestion and/or absorption through exposed area (Best and Fischer 1992). For example,
waterfowl are exposed to granular insecticides when sieving for crop residues in
pond and drenched soils or intake of grit (Best and Fischer 1992). Parsons et al.
(2010) reported the pesticide contamination in water birds in some submerged crop
(corn, wheat, and rice) fields in the USA and Canada. Granular forms of the pesticide
differ in size, colour, shape, surface texture, carrier material composition, pesticide
load per granule, and activity period in the field after application (Gionfriddo and
Best 1996; Stafford et al. 1996). Besides primary poisoning, second-generation granular form of pesticides (such as carbofuran) causes secondary poisoning, for example, in raptors, consuming contaminated birds or other wild animals or been
contaminated to such granules led to regional population declines (Sánchez-Bayo
et al. 2013).
Seeds Coated with Insecticide
Seed treatment with organophosphate and carbamates is very common in developing countries but having been replaced by neonicotinoids (such as imidacloprid) and
is no longer approved in some developed countries. Conventional seed treatment by
applying pesticides for crop protection was widely used in the UK during the year
between 1992 and 2002 (Garthwaite et al. 2003; Prosser and Hart 2005). In Spain,
among 18 pesticides permitted for coating of seeds of cereals (MAGRAMA 2013),
thiram and maneb are used as fungicides (among the 14), and the rest four are as
insecticides. In India, carbofuran-treated seeds have been widely applied, and as a
consequence, a number of birds are regularly exposed, though not being reported till
date (Venkataramanan and Sreekumar 2012). These pesticide-coated seeds may
serve as food source for granivorous birds, which may be fatal to flocks by wilful
consumption and subsequent death of carnivorous birds for consumption of contaminated primary population (secondary poisoning) (Fletcher et al. 1996; Almeida
et al. 2010). The incidence of avian poisoning due to seed treatment has been
reported by Pain et al. (2004) where 15 sarus cranes (Grus antigon) and 3 common
cranes (Grus grus) were intoxicated by monocrotophos at Bharatpur reserve forest
in India. Intoxication from treated seeds depends on various factors like sowing
area, lethality of pesticide and its concentration on the seed, density of the disclosed
seed, and accessibility of alternative food materials (UNEP/CMS/SCC18/Inf.10.9.1,
2014). Again, the risk of exposure to the treated seeds will depend on how likely the
birds are to consume them. Birds can avoid the toxic seeds due to the appearance
and repugnance of the food or due to feeling of distress due to sublethal toxic effect
through a mechanism of conditioned antipathy (Lopez-Antia et al. 2014).
3 Toxic Effects of Pesticides on Avian Fauna
food (Best 1995). These birds are unable to distinguish granular form of pesticide
because the carrier medium of pesticide granules is sand (silica) which is the ideal
natural grit material (Mineau 2009). Therefore, particulate forms of pesticide may
enter into the body of avian fauna either through intentional or unintentional ingestion and/or absorption through exposed area (Best and Fischer 1992). For example,
waterfowl are exposed to granular insecticides when sieving for crop residues in
pond and drenched soils or intake of grit (Best and Fischer 1992). Parsons et al.
(2010) reported the pesticide contamination in water birds in some submerged crop
(corn, wheat, and rice) fields in the USA and Canada. Granular forms of the pesticide
differ in size, colour, shape, surface texture, carrier material composition, pesticide
load per granule, and activity period in the field after application (Gionfriddo and
Best 1996; Stafford et al. 1996). Besides primary poisoning, second-generation granular form of pesticides (such as carbofuran) causes secondary poisoning, for example, in raptors, consuming contaminated birds or other wild animals or been
contaminated to such granules led to regional population declines (Sánchez-Bayo
et al. 2013).
Seeds Coated with Insecticide
Seed treatment with organophosphate and carbamates is very common in developing countries but having been replaced by neonicotinoids (such as imidacloprid) and
is no longer approved in some developed countries. Conventional seed treatment by
applying pesticides for crop protection was widely used in the UK during the year
between 1992 and 2002 (Garthwaite et al. 2003; Prosser and Hart 2005). In Spain,
among 18 pesticides permitted for coating of seeds of cereals (MAGRAMA 2013),
thiram and maneb are used as fungicides (among the 14), and the rest four are as
insecticides. In India, carbofuran-treated seeds have been widely applied, and as a
consequence, a number of birds are regularly exposed, though not being reported till
date (Venkataramanan and Sreekumar 2012). These pesticide-coated seeds may
serve as food source for granivorous birds, which may be fatal to flocks by wilful
consumption and subsequent death of carnivorous birds for consumption of contaminated primary population (secondary poisoning) (Fletcher et al. 1996; Almeida
et al. 2010). The incidence of avian poisoning due to seed treatment has been
reported by Pain et al. (2004) where 15 sarus cranes (Grus antigon) and 3 common
cranes (Grus grus) were intoxicated by monocrotophos at Bharatpur reserve forest
in India. Intoxication from treated seeds depends on various factors like sowing
area, lethality of pesticide and its concentration on the seed, density of the disclosed
seed, and accessibility of alternative food materials (UNEP/CMS/SCC18/Inf.10.9.1,
2014). Again, the risk of exposure to the treated seeds will depend on how likely the
birds are to consume them. Birds can avoid the toxic seeds due to the appearance
and repugnance of the food or due to feeling of distress due to sublethal toxic effect
through a mechanism of conditioned antipathy (Lopez-Antia et al. 2014).
3 Toxic Effects of Pesticides on Avian Fauna