Why were we concerned about bald eagle populations?
Through a combination of habitat loss, hunting, and pesticide pollution (Ex: dichlorodiphenyltrichloroethane or DDT) the bald eagle population in the United States began to decline rapidly in the early 1900s. DDT specifically continued to be a cause of major concern as it caused the eggshells of bald eagles to be too soft leading to failed hatching. DDT remained in production and was used heavily until 1972, however, even after it was banned, bald eagle populations had already plummeted so drastically that bald eagles were listed as endangered by the U.S. Fish and Wildlife Service in 1976. In an effort to recover the national presence of this bird, conservationists began a translocation strategy that involved the collection of the first batch of eggs laid by nesting pairs and the hatching of the eggs in captivity. Once the eagles were young adults they were released into areas across the U.S. that had previously had stable bald eagle populations.
Were there any residual effects of translocation?
While translocation assisted in the rejuvenation of this species, it also resulted in a genetic bottleneck that limited the genetic diversity found within geographically distinct bald eagle populations. It is essential to explore the relatedness of these groups to understand the level of genetic diversity that has remained which can then inform future management strategies. One way this can be done is through examination of Single Nucleotide Polymorphisms (SNPs) in sequenced bald eagle genomes via computational analysis. The programs Structure, King, Spider, Plink, and R were used to compare 27 individuals within three geographically distinct populations. The information provided by SNPs allows for the comparison of diversity while also identifying the original location of that specific bird prior to the area it inhabits due to its translocation.