Incidence of heavy metals in feathers of birds in a human‐impacted forest, south‐west Nigeria

Hazardous wastes and heavy metal are detrimental to all life forms (Dixit et al., 2015; Sharma, Katnoria, Kaur, & Nagpal, 2015). Organic forms of heavy metals such as mercury and lead can accumulate in living tissues; the health implication ranges from low immunocom‐ petence, failed reproduction to high mortality in a number of taxa (Falq et al., 2011; Fritsch et al., 2010; Hollamby et al., 2004; Kerby, Richards‐Hrdlicka, Storfer, & Skelly, 2010; Scheifler et al., 2006; Webb & Leake, 2006). Unprecedented levels of heavy metals and their neg‐ ative role in biodiversity loss and habitat degradation pose major eco‐ logical concerns (Ayangbenro & Babalola, 2017; Kibria, 2016; Sharma et al., 2015). Despite this fact, less attention is focused on monitoring the levels and impact of heavy metals in the western part of Nigeria. Birds are promising biomonitoring species for heavy metals and xenobiotic based on their use in nondestructive avian matrices, for ex‐ ample feather, blood and egg; and bioavailability, and biotransference in dose‐dependent responses (Becker, 2003; Furness & Greenwood, 1993; Roux & Marra, 2007; Swaileh & Sansur, 2006). Also, as feathers grow in birds, heavy metals are sequestered in the sulfhydryl group of the keratin; the metal residues remained resistant to change in older feather as blood supply stops (Burger, 1993). We investigated the inci‐ dence of heavy metals in passerine birds inhabiting a human‐impacted forest in Ilara‐Mokin, south‐west Nigeria.