Carrasco-Garcia, R., Barroso, P., Perez-Olivares, J., Montoro, V., & Vicente, J. (2018). Consumption of Big Game Remains by Scavengers: A Potential Risk as Regards Disease Transmission in Central Spain. Frontiers in Veterinary Science, 5. doi:10.3389/fvets.2018.00004

Havermans, C., & Smetacek, V. (2018). Bottom-up and top-down triggers of diversification: A new look at the evolutionary ecology of scavenging amphipods in the deep sea. Progress in Oceanography, 164, 37-51. doi:10.1016/j.pocean.2018.04.008

Sugiura, S., & Hayashi, M. (2017). Functional compensation by insular scavengers: The relative contributions of vertebrates and invertebrates vary among islands. Ecography, 41(7), 1173-1183. doi:10.1111/ecog.03226

Scavengers play a fundamental role in the environment through the removal of carrion, or dead animal flesh^[1], serving as an environmental sanitation surface^[2]. Carcass removal by vertebrate scavengers results in a larger diffusion of nutrients into the overall food web compared to removal of carcasses by microorganisms or invertebrate scavengers^[1].

Scavenging unites animals which normally would not come into contact^[3], and results in the formation of highly structured and complex communities^[2] which engage in non random interactions^[4]. Scavenging communities function in the redistribution of energy obtained from carcasses and reducing decomposition associated diseases^[4]. Oftentimes vertebrate scavenger communities differ in consistency due to carcass size and carcass types, as well as by seasonal effects as consequence of differing invertebrate and microbial activity.^[5]

Competition amongst scavengers for carrion may occur resulting in the inclusion and exclusion of certain scavengers from access to carrion, shaping the scavenger community^[5]. Seasonal changes may result in the alteration of competition amongst scavengers. During cooler seasons, it has been observed that competition amongst scavengers decreases as carrion decomposes at a slower rate and therefore is available for a longer period of time^[5]. Such longer persistence time also results in the increase of scavenger species present to feed from the carrion^[5].

Alterations in scavenging communities may result in drastic changes to the scavenging community in general, reduce ecosystem services and have detrimental effects on animal and humans^[4]. The reintroduction of gray wolves (Canis lupus) into Yellowstone National Park in the United States caused drastic changes to the prevalent scavenging community, resulting in the provision of carrion to many mammalian and avian species^[5]. Likewise, the reduction of vulture species in India lead to the increase of opportunistic species such as feral dogs and rats^[2]. The presence of both species at carcasses resulted in the increase of diseases such as rabies and bubonic plague in wildlife and livestock, as feral dogs and rats are transmitters of such diseases^[2]. Furthermore, the decline of vulture populations in India has been linked to the increased rates of anthrax in humans due to the handling and ingestion of infected livestock carcasses^[2]. An increase of disease transmission has been observed in mammalian scavengers in Kenya due to the decrease in vulture populations in the area, as the decrease in vulture populations resulted in an increase of the number of mammalian scavengers at a given carcass along with the time spent at a carcass.^[2]

Scavenging may provide a direct and indirect method for disease transmission of animals. More specifically, scavengers of infected carcasses may become hosts for certain pathogens and consequently vectors of disease themselves^[6]. An example of this phenomenon is the increased transmission of tuberculosis observed when scavengers engage in eating infected carcasses^[6]. Likewise, the ingestion of bat carcasses infected with rabies virus by striped skunks (Mephitis mephitis) resulted in increased infection of these organisms with rabies virus.

A major vector of transmission of diseases are various bird species, with outbreak being influenced by such carrier birds and their environment^[7]. An increase of transmission of avian influenza virus to chickens by domestic ducks from Indonesian farms permitted to scavenge surrounding areas was observed in 2007^[8]. The scavenging of ducks in rice paddy fields in particular resulted in increased contact with other bird species feeding on leftover rice, which may have contributed to increased infection and transmission of the avian influenza virus. The domestic ducks may not have demonstrated symptoms of infection themselves, though were observed to excrete high concentrations of the avian influenza virus. Similarly, an avian cholera outbreak during December 2006 to March 2007 off the coast Newfoundland, Canada resulted in the mortality of many marine bird species.^[7]  Interestingly, the transmission, perpetuation and spread of the outbreak was mainly restricted to gull species who scavenge for food in the area.^[8]

Transmission of diseases may occur indirectly through animal by-products.^[6]

Many species that scavenge face persecution globally. Vultures in particular have faced incredible persecution and threats by humans.

Poisoning of the food sources of these animals is a common form of persecution, and as vulture feed communally many organisms may be affected at a given feeding period.^[2] Poisoning of the vulture food source such as various carnivorous species with the drug diclofenac has resulted in a 95% decline of Gyps vultures in Asia, and as a result diclofenac was banned by regional governments in 2006.^[2] Poisoning of carnivorous species that are predators of game species is still a common practice in Europe and consequently contributes to the poisoning of vultures.^[2]

Habitat loss has also contributed to the decline of vulture species, specifically in West Africa due to the growing human population.^[2]

Food shortage has also affected various vulture populations in West Africa, mainly as a result of overhunting of vulture food sources as well as changes in livestock husbandry.^[2] Food shortage is a major threat to vulture populations as it has been correlated with lower breeding success and high mortality rates in juvenile vultures.^[2]

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Your article starts off very strong, the lead section provides a strong general overview of the concept and provides the most essential information on the topic, such as what you added to the definition of a scavenger and the factors that affect scavenging. What you added to the article is also very well organized, starting with the effect of scavengers on the environment, elaborating on that before discussing the consequences related with scavenging. As such, your ideas flow logically from one section to the next. Your sections are also well balanced in terms of the amount of content in each segment, and you provided plenty of examples throughout to support the information presented, which was a great addition to the article. All of the information added is also presented in a neutral tone. Most of your sections are well researched, using multiple references throughout each section and not relying too heavily on any one reference. Your section on the threats to scavengers only uses one source throughout, so another referenced example of threats to another species perhaps would add strength to this section. It is not incredibly common throughout the article, but you may also want to review where you put your references throughout the article, as the adding citation training suggests that references are usually put at the end of sentences and always after punctuation marks, even if not at the end of sentences. There were also a few sentences that were a little confusing or unclear. In your example of avian influenza transmission it was a little unclear at first which species of bird was the scavenger, the chickens or ducks. Also, when you mention that disease transmission can occur through animal by-products you could elaborate and provide information on how the transmission occurs or what by-products transmission can occur through. Other than those few areas to edit, the article is really well done and I really liked how much research you did and how many examples you provided throughout.Sjh1917 (talk) 15:47, 7 November 2018 (UTC)