Inbreeding Could Pose Threat to White-Tailed Eagle Skip to content

Inbreeding Could Pose Threat to White-Tailed Eagle

By Ragnar Tómas

White-tailed Eagle Haförn Hafernir
Photo: Golli.

The Icelandic white-tailed eagle could be threatened by genetic homogeneity and inbreeding, a new article in the journal Molecular Ecology notes. The eagle’s fertility is one-third that of its Scandinavian cousins.

Icelandic and Greenlandic eagles genetically more homogeneous than their cousins

A study of the Icelandic white-tailed eagle and its cousins ​​is reported on in an article that was recently published in the scientific journal Molecular Ecology. Among other things, the authors of the study processed blood samples from Icelandic eaglets that had been collected since the turn of the century.

Professor Snæbjörn Pálsson at the University of Iceland managed the project. He told RÚV that Greenlandic and Icelandic eagles differ from their cousins ​​in the Nordic countries, mainly because of how genetically homogeneous they are and also because there are indications that the Icelandic eagle suffers from inbreeding.

As noted in the article: “island populations may suffer from low genetic variation, and thus be more prone to inbreeding depression or extinction, both due to founder effect bottlenecks during colonization and as a result of increased genetic drift in small isolated populations.”

Sveinbjörn explained to RÚV that this low genetic variation on the islands, especially in Iceland, could explain why fertility rates of the white-tailed eagle in Iceland are very low, or approximately one-third of the fertility rates of its cousins in Scandinavia.

READ MORE: Eagle Empire from the Iceland Review magazine

The Icelandic white-tailed eagle was almost eradicated by Icelanders during the 20th century. It was protected in 1914, but the population subsequently grew slowly; rates of population growth have, however, slightly improved after the practice of leaving out poisoned carcasses to kill off Arctic foxes was banned in 1964. The population of white-tailed eagles in Iceland now numbers approximately ninety pairs.

“Nevertheless, fertility rates are low compared to white-tailed eagles in mainland Europe,” an article on the website of the University of Iceland from last December notes.

Inbreeding could be detrimental to the eagle

Inbreeding within the eagle population could also serve to increase the risk of harmful mutations taking hold and causing harm to the population. This also makes the eagle less capable of adapting to changes such as new diseases, changes in prey, climate, temperature, and more.

Professor Snæbjörn Pálsson told RÚV that the next step in the research would be examining individual genes in the eagle’s genome: “Examining genes related to the breakdown of toxins, for example. Persistent organic toxins are known to have a negative impact on the life expectancy of white-tailed eagles in the twentieth century,” Snæbjörn observed.

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