Proximity to paths and roads is a burden for white-tailed sea eagles

Date: October 7, 2019

Source: Forschungsverbund Berlin

The white-tailed sea eagle is known for reacting sensitively to disturbances. However, research into which factors have which effects on the animals and how these impacts influence breeding success has so far only just begun. A research team led by Dr. Oliver Krone from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) has now measured concentrations of the hormone corticosterone and its metabolic products in white-tailed sea eagles in northern Germany and correlated these values with potential causes of "stress." They found that the levels of corticosterone in the birds' urine are higher the closer a breeding pair's nest is to paths or roads. From this, the scientists derive implications for the management and protection of white-tailed sea eagles, in particular for protection zones around the nests. The study was published in the journal General and Comparative Endocrinology.

Important areas of distribution of the sea eagle in Germany -- such as the Mecklenburg Lake District or the Baltic Sea coast -- are also attractive tourist regions. As a result, visitor numbers in core breeding areas are high and continue to rise. Since typical tourist activities -- hiking, cycling, and water sports -- focus on experiencing nature, researchers see a potential conflict between visitors and the sensitive animals. "In order to either confirm or refute this assumption, we measured the level of the hormone corticosterone in urine samples of 52 white-tailed sea eagles in the Usedom Island Nature Park in spring and early summer," explains Dr. Oliver Krone of Leibniz-IZW, head of the study.

https://www.sciencedaily.com/releases/2019/10/191007100416.htm

Golden and sea eagle decline since Dark Ages mapped

The decline in numbers of golden and white-tailed sea eagles in Britain and Ireland since the time of King Arthur has been mapped by the RSPB.

Researchers looked at places named after eagles in Gaelic and Old English to help estimate populations of the birds in AD500.

From the Dark Ages, they drew on historical material and studies to map pairs of the raptors to the present.

The RSPB said the maps painted "a sad picture of decline".

Published in Bird Study, the journal of the British Trust for Ornithology, the study suggests both species were once found across lowland and upland Britain and Ireland.

There were an estimated 1,000 to 1,500 pairs of golden eagles in AD500, when Arthur was said to have been a mythical king, or a real-life warlord.

Continued:  http://www.bbc.co.uk/news/uk-scotland-highlands-islands-18352135