Feathers accurately reflect blood mercury at time of feather growth in a songbird

Bottini, Claire; MacDougall‐Shackleton, Scott A.; Branfireun, Brian A.; Hobson, Keith A.

doi:10.1016/j.scitotenv.2021.145739

Cited by 24 publications

(13 citation statements)

References 47 publications

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“…We captured birds via mist nets, using playback of adult song and juvenile distress calls to attract song sparrows to the nets. These birds were part of unrelated experiments 28 , 29 , 38 , 72 and were used in this study in accordance with guidelines to reduce the number of animals used in research wherever possible (Canadian Council on Animal Care, CCAC).…”

Section: Methodsmentioning

confidence: 99%

Uropygial gland microbiota differ between free-living and captive songbirds

Grieves

Bottini

Gloor

et al. 2022

Sci Rep

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Symbiotic microbes can affect host behavior and fitness. Gut microbiota have received the most study, with less attention to other important microbial communities like those of scent-producing glands such as mammalian anal glands and the avian uropygial gland. However, mounting evidence suggests that microbes inhabiting scent-producing glands play an important role in animal behavior by contributing to variation in chemical signals. Free-living and captive conditions typically differ in social environment, food diversity and availability, disease exposure, and other factors—all of which can translate into differences in gut microbiota. However, whether extrinsic factors such as captivity alter microbial communities in scent glands remains an open question. We compared the uropygial gland microbiota of free-living and captive song sparrows (Melospiza melodia) and tested for an effect of dietary manipulations on the gland microbiota of captive birds. As predicted, the uropygial gland microbiota was significantly different between free-living and captive birds. Surprisingly, microbial diversity was higher in captive than free-living birds, and we found no effect of dietary treatments on captive bird microbiota. Identifying the specific factors responsible for microbial differences among groups and determining whether changes in symbiotic microbiota alter behavior and fitness are important next steps in this field.

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Section: Methodsmentioning

confidence: 99%

Uropygial gland microbiota differ between free-living and captive songbirds

Grieves

Bottini

Gloor

et al. 2022

Sci Rep

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“…We acknowledge that there have been mixed recommendations on using feathers, especially flight feathers, to draw conclusions about Hg exposure in birds (Bond and Diamond 2008;Peterson et al 2019;Low et al 2020). Hg levels in feathers generally correspond with the order of moult, with the first-moulted feathers containing the highest Hg levels (Furness et al 1986;Bottini et al 2021;Gatt et al 2021). Most passerines replace their tail feathers about halfway through their moult beginning with the innermost tail feathers (Pyle 1997).…”

Section: Range-wide Hg Predictorsmentioning

confidence: 99%

“…During the period of feather growth, Hg in blood becomes encapsulated into the feathers and remains inert thereafter (Furness et al 1986). Hg content in the blood includes a combination of recent dietary exposure and body burden accumulated since the last moult cycle (Honda et al 1986;Braune and Gaskin 1987;Thompson et al 1991;Monteiro and Furness 2001;Bottini et al 2021). Feathers are the main pathway for birds to rid their body of Hg; 70-93% of the body burden gets incorporated into feathers (Honda et al 1986;Braune and Gaskin 1987;Agusa et al 2005;Whitney and Cristol 2017a;Albert et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Mercury toxicity risk and corticosterone levels across the breeding range of the Yellow-breasted Chat

Mancuso

Hodges

Grosselet³

et al. 2022

Ecotoxicology

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Mercury (Hg) is an environmental contaminant that can negatively impact human and wildlife health. For songbirds, Hg risk may be elevated near riparian habitats due to the transfer of methylmercury (MeHg) from aquatic to terrestrial food webs. We measured Hg levels in tail feathers sampled across the breeding range of the Yellow-breasted Chat (Icteria virens), a riparian songbird species of conservation concern. We assessed the risk of Hg toxicity based on published benchmarks. Simultaneously, we measured corticosterone, a hormone implicated in the stress response system, released via the hypothalamus-pituitary-adrenal axis. To better understand range-wide trends in Hg and corticosterone, we examined whether age, sex, subspecies, or range position were important predictors. Lastly, we examined whether Hg and corticosterone were correlated. Hg levels in chats were relatively low: 0.30 ± 0.02 µg/g dry weight. 148 out of 150 (98.6%) had Hg levels considered background, and 2 (1.6%) had levels considered low toxicity risk. Hg levels were similar between sexes and subspecies. Younger chats (<1 year) had higher Hg levels than older chats (>1 year). Hg levels were lowest in the northern and central portion of the eastern subspecies’ range. Corticosterone concentrations in feathers averaged 3.68 ± 0.23 pg/mm. Corticosterone levels were similar between ages and sexes. Western chats had higher levels of corticosterone than eastern chats. Hg and corticosterone were not correlated, suggesting these low Hg burdens did not affect the activity of the hypothalamus-pituitary-adrenal axis. Altogether, the chat has low Hg toxicity risk across its breeding range, despite living in riparian habitats.

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“…The overall goal of our study was to examine Hg concentrations in glaucous-winged gull feathers to determine if gulls reflected long-term trends in Hg deposition of Pacific ecosystems. We examined Hg in head, flank, and primary feathers from museum collections, as feathers reflect the Hg body burden during growth. − We predicted that, because gulls have shifted to lower trophic and/or terrestrial/freshwater prey over time, THg trends in gull feathers would have increased at a slower rate than trends in North Pacific Ocean food webs. Mercury is also a strong indicator of marine foraging in seabirds; therefore, stable Hg trends in gulls may provide further evidence of a shift to freshwater and/or terrestrial prey.…”

Section: Introductionmentioning

confidence: 99%

Stable Mercury Trends Support a Long-Term Diet Shift Away from Marine Foraging in Salish Sea Glaucous-Winged Gulls over the Last Century

Choy

Blight

Elliott

et al. 2022

Environ. Sci. Technol.

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Marine predators are monitored as indicators of pollution, but such trends can be complicated by variation in diet. Glaucous-winged gulls (Larus glaucescens) have experienced a dietary shift over the past century, from mainly marine to including more terrestrial/freshwater inputs, with unknown impacts on mercury (Hg) trends. We examined 109-year trends in total mercury (THg) and methylmercury (MeHg) concentrations in glaucous-winged gull feathers (1887− 1996) from the Salish Sea. Adult flank feathers had higher MeHg concentrations than immature feathers, and males head feathers had higher THg concentrations than females. Overall, we found no evidence of a trend in feather MeHg or THg concentrations over time from 1887 to 1996. In the same individuals, δ 15 N, δ 13 C, and δ 34 S declined over time in gull feathers. In comparison, egg THg concentrations declined from 1970 to 2019 in two species of cormorants, likely reflecting decreases in local Hg sources. We conclude that diet shifts through time may have countered increased Hg deposition from long-range transport in glaucous-winged gulls. The lack of Hg trends over time in glaucous-winged gull feathers provides additional support that these gulls have decreased the amount of marine forage fish in their diet.

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Feathers accurately reflect blood mercury at time of feather growth in a songbird

Cited by 24 publications

References 47 publications

Uropygial gland microbiota differ between free-living and captive songbirds

Uropygial gland microbiota differ between free-living and captive songbirds

Mercury toxicity risk and corticosterone levels across the breeding range of the Yellow-breasted Chat

Stable Mercury Trends Support a Long-Term Diet Shift Away from Marine Foraging in Salish Sea Glaucous-Winged Gulls over the Last Century

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