Contrasting levels of heavy metals in the feathers of urban pigeons from close habitats suggest limited movements at a restricted scale

The adaptive function of melanin-based plumage coloration to trace metals

“…Some environmental factors may have hidden the correlation between coloration and metal concentrations at capture time. Although birds were captured from closely located sites, we cannot exclude local differences in pollution levels, known to change even at a small scale [1,21]. Moreover, habitat use may vary among differently coloured pigeons, as is often the case in polymorphic species [22].…”

“…Feathers were mineralized as described in Frantz et al [21]. Feathers were washed vigorously with 0.25 M NaOH solution, rinsed energetically three times in ultrapure water (Milli-Q purified) to remove external contamination [5], left for 1 h in ultrapure water, dried for 12 h at 808C to dry mass, crushed to powder and weighed to the nearest 0.1 mg. Feathers were then digested twice in 1 ml nitric acid (67%), followed by a final digestion in 1 ml hydrogen peroxide (30%).…”

Influence of taxa, trophic level, and location on bioaccumulation of toxic metals in bird’s feathers: A preliminary biomonitoring study using multiple bird species from Pakistan

“…Some species have biological habits that increase the likelihood of exposure to contaminants and, in that way can produce relevant information that would be missed if only water or soil would be analyzed. Most recently, urbanelydwelled species like feral pigeon (Columba livia) have also been used for the environmental monitoring of urban environment (Brait and Antoniosi-Filho, 2011;Frantz et al, 2012). Measuring the pollutant concentrations directly in the internal tissues of birds is well in practice and proven to be the best indicator for bioaccumulative compounds.…”

“…But recently, the need for alternative, noninvasive tissues for biomonitoring has arisen for various ethical, practical and conservationist reasons. Instead of sacrificing living birds, different non-invasive matrices such as eggs (Jaspers et al, 2005;Van den Steen et al, 2006;Eens et al, 2013) and feathers (Jaspers et al, 2004;Kim and Koo, 2007;Frantz et al, 2012) are commonly used for biomonitoring. Despite all its pros and cons, feathers offer many advantages as a useful non-destructive biomonitoring material and are often considered to be an excellent tool for monitoring bioaccumulativ compounds (Malik and Zeb, 2009;Garcia-Fernandez et al, 2013).…”

“…Over the past few decades, excessive deposition of heavy metals in the environment and their negative impacts on ecosystems and organisms has attracted the attention of ecotoxicologists throughout the globe (Frantz et al, 2012). Heavy metals are persistent elements and ubiquitous in the environment due to both naturally occurring geological cycles and anthropogenic activities.…”