The yellow-shouldered blackbird (Agelaius xanthomus) is indigenous to the island of Puerto Rico. It is speculated that this species is derived from the red-winged blackbird which is native to the Haitian Island. Physically the yellow-shouldered blackbird looks just like it sounds, black with brachial yellow patches around the shoulders of the bird. The males are usually larger,heavier and have larger wings than the females of the species. On average the adult birds measure between twenty to twenty-three centimeters and weigh between thirty-five to forty-five grams. Although they are labeled as omnivores these birds have a diet that consists mostly of insects (Beauty of birds,2011).The breeding season for this species usually begins in
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This is due to the fact that it has been affected by predation and parasitism for so many years but still hasn’t developed any manner of defending itself from it’s predators. The fact that after all these years there still hasn’t been any sort of behavioral adaptation that would increase their reproductive success rate or increase their chances of survival prompts researchers to want to learn more about its evolutionary history and compare it to other birds that are believed to be closely related.The yellow-shouldered blackbird is commonly linked to the red-winged blackbird which is usually found in North America so by studying both species researchers are able to get better understanding of how the yellow-shouldered blackbird was able to adapt to tropical habitats when it’s ancestors came from an entirely different environment. By studying the blackbird researchers also gain insight to the overall health status in which it resides (Post and Wiley, …show more content…
This program or method consisted of capturing the cowbirds in decoy traps, which were often used in Michigan also for the purpose of cowbird control, and ended with the captured birds being killed. These traps were placed on cowbird feeding grounds as well as in blackbird breeding areas in order to capture as many targets as possible. The amount of cowbirds captured between the years of 1985 and 2003 was about 30,000 this led to the decrease of parasitised blackbird eggs from 95% (1971-1985) to 10% (after 1995). In addition to this method, artificial blackbird nesting areas were created in order to prevent parasitism and predation as well as improve the amount of viable offspring blackbirds produced (Cruz et al, 2005). The idea of cowbird removal was based on a similar situation in which the brown-headed cowbird was removed from kirtland’s warbler which resulted in an increase of warbler offspring. In regards to the artificial nesting areas, the blackbird’s quickly adapted and accepted the nest boxes. These nest boxes were placed in areas which blackbirds never really used as breeding grounds in order to be able to better protect the nests from cowbird parasitism (Wiley et al,
This is due to the fact that it has been affected by predation and parasitism for so many years but still hasn’t developed any manner of defending itself from it’s predators. The fact that after all these years there still hasn’t been any sort of behavioral adaptation that would increase their reproductive success rate or increase their chances of survival prompts researchers to want to learn more about its evolutionary history and compare it to other birds that are believed to be closely related.The yellow-shouldered blackbird is commonly linked to the red-winged blackbird which is usually found in North America so by studying both species researchers are able to get better understanding of how the yellow-shouldered blackbird was able to adapt to tropical habitats when it’s ancestors came from an entirely different environment. By studying the blackbird researchers also gain insight to the overall health status in which it resides (Post and Wiley, …show more content…
This program or method consisted of capturing the cowbirds in decoy traps, which were often used in Michigan also for the purpose of cowbird control, and ended with the captured birds being killed. These traps were placed on cowbird feeding grounds as well as in blackbird breeding areas in order to capture as many targets as possible. The amount of cowbirds captured between the years of 1985 and 2003 was about 30,000 this led to the decrease of parasitised blackbird eggs from 95% (1971-1985) to 10% (after 1995). In addition to this method, artificial blackbird nesting areas were created in order to prevent parasitism and predation as well as improve the amount of viable offspring blackbirds produced (Cruz et al, 2005). The idea of cowbird removal was based on a similar situation in which the brown-headed cowbird was removed from kirtland’s warbler which resulted in an increase of warbler offspring. In regards to the artificial nesting areas, the blackbird’s quickly adapted and accepted the nest boxes. These nest boxes were placed in areas which blackbirds never really used as breeding grounds in order to be able to better protect the nests from cowbird parasitism (Wiley et al,