Pesticide Residues in Birds and Mammals - Pesticides: Evaluation of Environmental Pollution - page 435

again an application of bromadiolone baits to control water voles in Northern Switzerland
killed at least 40 red foxes. In 2002, hundreds of nontarget wildlife deaths, including some
individuals of the saker falcons ( Falco cherrug ), corsac foxes ( Vulpes corsac ), and Pallas' cats
( Otocolobus manul ), were detected in Mongolia, following the application of bromadiolone-
treated wheat grains that were spread by aircraft over large areas of steppe grassland to
control an outbreak of Brandt's voles ( Microtus brandti ) (Winters et al. 2010).
In recent years, concern has grown also on the potential sublethal effects of AR expo-
sures to animals, due to their widespread and large-scale occurrence. Monitoring of
pesticide residues in many countries has shown the wanted or unwanted extension of
the problem (see Tables 14.5 and 14.6), and the situation has been particularly well docu-
mented in the United Kingdom (Newton et al. 1990; McDonald et al. 1998; Shore et al.
1999, 2003; Dowding et al. 2010; Walker et al. 2010), France (Berny et al. 1997; Fournier-
Chambrillon et al. 2004; Lemarchand et al. 2010; Sage et al. 2010), United States (Stone
et al. 1999, 2003), Canada (Howald et al. 1999; Albert et al. 2010), and, especially, New
Zealand (Murphy et al. 1998; Eason et al. 2002; Spurr et al. 2005; Hoare and Hare 2006).
Usually, the pattern of exposure to ARs reflects usage patterns in each region or country
considered.
New Zealand is an island country particularly vulnerable, which has now lost over
40% of its prehuman land-bird fauna (Atkinson 2001; Clout and Russell 2006). The rea-
son is that biological invasions of alien mammals have devastating effects principally
on insular ecosystems, affecting wildlife populations and biodiversity in different ways
(Atkinson 2001; Courchamp et al. 2003; Jones et al. 2008; Gibbs 2009). Warfarin, broma-
diolone, and, more recently, brodifacoum, which have been used since at least 1980, have
been the AR-type toxicants of choice for the eradication of introduced rats from offshore
islands in New Zealand (Towns and Broome 2003; Hoare and Hare 2006; Howald et al.
2007). By the end of 2004, there were 218 successful eradications of 17 different alien
mammal species reported from around 90 New Zealand islands (Towns and Broome
2003; Clout and Russell 2006). Pioneering techniques that have been developed, which
included the advent of new rodenticide delivery techniques such as aerial broadcast or
the use of pulsed rather than continuous baiting strategies, encouraged the application
of similar campaigns in islands of other parts of the world (Howald et al. 1999; Taylor et al.
2000; Thorsen et al. 2000; Donlan et al. 2003; Orueta et al. 2005). Invasive rodents have
been eradicated from at least 284 islands worldwide, totaling around 476 km 2 (Howald
et al. 2007).
14.6.2.1 Birds
Based on necropsy findings and analytical results, cases of confirmed or suspected lethal
effects after direct AR exposure through the consumption of poisoned baits in wild birds
have been described in the literature, and the species involved included domestic pigeons,
crested wood partridges ( Rollulus roulroul ) and other partridges, New Zealand robins
( Petroica australis ), little spotted kiwis ( Apteryx owenii ), western wekas ( Gallirallus australis ),
pukekos, saddlebacks ( Philesturnus carunculatus ), New Zealand kakas ( Nestor meridiona-
lis ), paradise shelducks, mallards ( Anas platyrhynchos ), and common ravens ( Corvus corax )
(Dowding et al. 1999; Howald et al. 1999; Taylor et al. 2000; Borst and Counotte 2002; Hoare
and Hare 2006; Sarabia et al. 2008; Olea et al. 2009; Guitart et al. 2010b). However, death
after secondary poisoning is a more common feature and had been especially diagnosed
in birds of prey (Borst and Counotte 2002; Stone et al. 2003; Murray and Tseng 2008; Albert
et al. 2010; Guitart et al. 2010b).