Belted Kingfishers are known for having bright coloration, composed of white, blue and reddish-brown feathers. As discussed in my other blog post, males do not have the reddish-brown band on their chest like the females do. The quality or color of a bird’s feathers may differ as a result of their diet.

 Belted kingfishers are primarily fish eaters or piscivores, and the fish they eat can have high levels of mercury in their bodies. Mercury is a chemical element which you have likely seen in a thermometer at some point. It is a very dangerous heavy metal that can lead to health consequences in humans (Science Daily). It turns out birds such as the belted kingfisher can also be negatively affected by mercury! By eating fish containing mercury, kingfishers can accumulate mercury in their system, through a process known as bioaccumulation. Mercury leaves the birds body slowly, and as they eat more fish, more mercury builds up. Belted kingfishers are some of the few birds who exhibit bioaccumulation. They are small with a fast metabolism, which means they eat a lot of fish and store a lot of toxins in their body (Bridge and Kelly 2013).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In areas where mercury has contaminated the water and the fish inhabiting that water, belted kingfishers have a high amount of mercury in their bodies. White and Cristol (2014) discovered that mercury exists in the blood and feathers of these birds in the form of methylmercury! Methylmercury is the most toxic form of mercury (Moore et al. 1999). The amount of mercury is much higher in birds living near mercury-contaminated waters than those living in non-contaminated regions. The high level of mercury in their bodies can actually affect the appearance of their feathers! It was found that male kingfishers with high amounts of mercury in their blood and feathers actually have brighter blue feathers. The reddish-brown feathers in females can also appear brighter (White and Cristol 2014).

Both rufous (reddish-brown) and blue feathers have melanin color pigments in them. Melanin pigments result in darker colored feathers and mercury can actually reduce the amount of melanin produced in bird feathers. With less melanin, feathers appear whiter, and therefore, brighter, due to an increase in the reflection of light. Whether varience in feather brightness affects interactions between males and females is unknown (White and Cristol 2014).

 

 

 

 

 

 

 

 

 

 

 

Mercury does effect belted kingfishers in ways other than altering feather appearance.  Another toxin which has contaminated waters via waste dumping are polychlorinated biphenyls or PCBs. PCBs are man-made chemicals used in the production of electrical and hydraulic equipment (EPA 2017). There are many types of PCBs that exist (Custer et al. 2010). They also have negative health effects on humans and likely top predators such as the belted kingfisher who eat contaminated fish. One way to estimate if belted kingfishers are significantly exposed to mercury and PCBs is to measure the amount of such chemicals in their prey and estimate how much of that prey kingfishers eat, such as Moore et al. did in their study (1999).

Using these estimates of chemicals in fish, it was found that methylmercury has been linked to a reduced number of eggs produced by each female, and therefore a reduction in reproductive success of females. However, from these estimates, PCBs don’t appear to have the same effect (Moore et al. 1999).

It turns out that both male and female belted kingfishers usually have near equal amounts of mercury in their bodies. However, mercury levels can differ among these birds depending on where they live and how close they are to a contaminated site. In fact, belted kingfishers who inhabit lakes and rivers actually tend to have more mercury in their blood than those who live in estuaries or marine areas. Mercury can be found in the eggs of belted kingfishers as well, but the amount of mercury per each egg differs among eggs. Piscivores such as the kingfisher, including loons and mergansers, tend to have more mercury in their eggs than insectivores (insect-eating birds) (Evers et al. 2004).

A sneak peek of a belted kingfishers nest with seven eggs cared for by the parents (a video by Wendy Bartter).

Just as mercury is present in eggs of belted kingfishers, PCBs are too (Custer et al. 2010). Belted kingfishers can have up to 7 eggs per clutch (Bridge and Kelly 2013) which are incubated by both the male and female, as seen in the video above. By monitoring belted kingfisher nests in an area where PCBs have been released into the environment, it can be directly determined if PCBs affect the number of eggs produced by belted kingfishers.

In a study conducted on the Hudson River in New York, USA it was found that belted kingfishers nests were not affected by PCB contamination (Bridge and Kelly 2013). In fact, the nests below the area of contamination actually had a higher success rate, where more fledglings left the nest than in areas above the contaminated area. Because these birds are equally successful in PCB contaminated and non-contaminated regions, it can be concluded that PCBs don’t seriously affect belted kingfisher reproduction (Bridge and Kelly 2013).

In addition to affecting feather color and reproductive success of belted kingfishers, mercury can also affect the unborn young within the egg. Mercury and other toxins have been shown to favor one sex, male or female, more so than the other in humans and wildlife. Typically, within a population, males and females exist in near equal numbers with a 1:1 ratio. However, it turns out that mercury shifts this ratio towards more females in belted kingfishers and tree swallows exposed to high mercury content.That is, within a clutch more females will be produced than males. Belted kingfishers are actually the first identified wildlife where mercury favors one sex over the other!

As discussed above, belted kingfishers can be seriously affected by toxins and pollutants such as mercury and PCBs. These birds are used as bioindicators because they are exposed to toxins. In other words, the amount of mercury in a bird can reveal the amount of mercury in the environment (Evers et al. 2004). It is important to understand how human-released chemicals affect wildlife so we can prevent future mistakes!

 

References:

Bridge ES, Kelly JF. 2013. Reproductive success of belted kingfishers on the upper Hudson River. Environ Toxicol Chem [Internet] [cited 2017 Nov 1]; 32(8):1855-1863. Available from:http://onlinelibrary.wiley.com.ezproxy.viu.ca/doi/10.1002/etc.2263/abstract doi:10.1002/etc.2263

Custer CM, Custer TW, Dummer PM. 2010. Patterns of organic contaminants in eggs of an insectivorous, an omnivorous, and a piscivorous bird nesting on the Hudson River, New York, USA. Environ Toxicol Chem [Internet] [cited 2017 Nov 3]; 29(10):2286-2296. Available from:http://dd6db2vc8s.search.serialssolutions.com/?ctx_ver=Z39.88-2004&ctx_enc=info%3Aofi%2Fenc%3AUTF-8&rfr_id=info%3Asid%2Fsummon.serialssolutions.com&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=Patterns+of+organic+contaminants+in+eggs+of+an+insectivorous%2C+an+omnivorous%2C+and+a+piscivorous+bird+nesting+on+the+Hudson+River%2C+New+York%2C+USA&rft.jtitle=Environmental+Toxicology+and+Chemistry&rft.au=Christine+M+Custer&rft.au=Thomas+W+Custer&rft.au=Paul+M+Dummer&rft.date=2010-10-01&rft.pub=Blackwell+Publishing+Ltd&rft.issn=0730-7268&rft.eissn=1552-8618&rft.volume=29&rft.issue=10&rft.spage=2286&rft.externalDocID=2359383621&paramdict=en-US doi:10.1002/etc.276

EPA. Polychlorinated Biphenyls (PCBs). [Internet] [cited 2017 Nov 2]. Available from: https://www.epa.gov/pcbs/learn-about-polychlorinated-biphenyls-pcbs

Evers DC, Burgess NM, Champoux L, Hoskins B, Major A, Goodale WM, Taylor RJ, Poppenga R, Daigle T. 2004. Patterns and interpretation of mercury exposure in freshwater avian communities in Northeastern North America. Ecotoxicology [Internet] [cited 2017 Nov 3]; 14:193-221. Available from: https://link.springer.com/article/10.1007%2Fs10646-004-6269-7

Moore DRJ, Sample BE, Suter GW, Parkhurst BR, Teed RS. 1999. A probabilistic risk assessment of the effects of methylmercury and PCBs on mink and kingfishers along East Fork Poplar Creek, Oak Ridge, Tennessee, USA. Environ Toxicol Chem [Internet] [cited 2017 Nov 2]; 18(12):1941-2953. Available from: http://dd6db2vc8s.search.serialssolutions.com/?ctx_ver=Z39.88-2004&ctx_enc=info%3Aofi%2Fenc%3AUTF-8&rfr_id=info%3Asid%2Fsummon.serialssolutions.com&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=A+probabilistic+risk+assessment+of+the+effects+of+methylmercury+and+PCBs+on+mink+and+kingfishers+along+East+Fork+Poplar+Creek%2C+Oak+Ridge%2C+Tennessee%2C+USA&rft.jtitle=Environmental+Toxicology+and+Chemistry&rft.au=Moore%2C+Dwayne+R.J&rft.au=Sample%2C+Bradley+E&rft.au=Suter%2C+Glenn+W&rft.au=Parkhurst%2C+Benjamin+R&rft.date=1999-12-01&rft.issn=0730-7268&rft.eissn=1552-8618&rft.volume=18&rft.issue=12&rft.spage=2941&rft.epage=2953&rft_id=info:doi/10.1002%2Fetc.5620181241&rft.externalDBID=n%2Fa&rft.externalDocID=10_1002_etc_5620181241&paramdict=en-US  doi: 10.1002/etc.5620181241

Science Daily. Mercury [Internet] [cited 2017 Nov 2]. Available from: https://www.sciencedaily.com/terms/mercury_(element).htm

White AE, Cristol DA. 2014. Plumage coloration in Belted Kingfishers (Megaceryle alcyon) at a mercury-contaminated river. BioOne [Internet] [cited 2017 Nov 1]; 37(2):144-152. Available from: http://www.bioone.org.ezproxy.viu.ca/doi/pdf/10.1675/063.037.0203 doi: 10.1675/063.037.0203