Biol 1500: Conservation Biology Animal Extinction

Animal Extinction
Name
Institution
Animal Extinction
Question 1
* What species did you research and why?
I selected the passenger pigeon for research. This species is also known as the wild pigeon or Ectopistes migratorius (Hedrick, 2018). The common name of the passenger pigeon was derived from the term “passager” which is French word that means "passing by." The species name was given due to the birds migratory habits. The scientific name of the species also describes the migratory characteristics of the species.
* Where was this species originally located and what sort of habitat did it occupy?
The extinct species was originally rampant in the east of the North American Rocky Mountains. It was also found across the great plains of the Atlantic coast and the south of Canada as well as northern Mississippi in the US (Hedrick, 2018). Its major habitat was the eastern deciduous forests. The wild pigeon habitat was mostly the mixed hardwood forests as the species relied on the forests for the nesting sites during spring. During the winter period, the wild pigeon depended on the hardwood forest to get food and roosting. The diet of the wild pigeon included chestnuts, acorns, berries and beechnuts as well as seeds from the forest.
* What categories of extinction vulnerabilities listed in Chapter 5 (attached) affected this species? List as many as apply.
The passenger pigeon was exposed to several extinction vulnerabilities which include:
* Narrow geographic range. The birds depended on the hardwood forests in North America where they travelled and produced in large numbers and thus were affected by deforestation.
* Hunting or harvesting by people. Native Americans and Europeans hunted wild pigeons during the 19th century. The meat of the species was sold as cheap food leading to large scale hunting of the wild pigeon for several years.
* Large home ran. The wild pigeon used to migrate and forage over wide areas making them an easy target for commercial hunters.
* Limited dispersal ability. The species was unable to adapt to the changing environment in the 19th century which witnessed massive deforestation. The hardwood forests were suitable for communal breeding and roosting.
* Seasonal migrations. The wild pigeon was described as nomadic due to the constant migration in search of shelter, food as well as the nesting grounds. Constant migration during the summer and winter made the birds vulnerable to various harsh climatic and reproduction conditions. They were also exposed to human hunting as they migrated.
* Specialized niche requirement. The wild pigeon was a gregarious and colonial species that roosted and bred communally and thus the birds required to be in large numbers to ensure they had optimum environment for breeding.
* What other biological or ecological traits may have contributed to its extinction?
The passenger pigeons had limited genetic diversity despite their large population in the 19th century. A genetic study that was conducted on these birds found out that the low genetic diversity in the species was due to natural selection. Natural selection is a side effect that could have had a significant effect on large species as well as species with cohesive populations such as the passenger pigeons (Hedrick, 2018). Natural selection reduces the genetic diversity of a specific species over large regions of a genome through background selection or selective sweeps. The passenger pigeons were also characterized by a fast rate of adaptive evolution as well as a rapid eradication of harmful mutations when they were compared to band-tailed pigeons. Some regions of the bird’s genome also had lower genetic diversity due to low rates of genetic recombination. Their low genetic diversity was also caused by the constant population instability of the species.
* Did it have one dominant feature that was predictive of extinction, or a combination of such features?
One of the predictive extinction characteristic of the passenger pigeon is the species communal roosting tendency. The passenger pigeon was a communal roosting species and it had selected roosting sites which provided sufficient food and shelter that could maintain their large numbers for a longer period. The decline of the natural forests, weather conditions and the increasing number of predators led to its extinction because of the inadequate environment for breeding (Hedrick, 2018). Therefore, the time spent on a single roosting site heavily relied on the weather conditions of the area and the level of human persecution. The wild pige...