Pennycott Tom, Bignal Eric, McCracken Davy
Scottish Chough Study Group, Ayr, UK.
Scottish Chough Study Group, Bridgend, Isle of Islay, UK.
Vet Rec. 2025;196(7):e4961. doi: 10.1002/vetr.4961. Epub 2024 Dec 26.
The breeding population of the red-billed chough (Pyrrhocorax pyrrhocorax) in Scotland has fallen in recent years, with all breeding pairs now confined to the Hebridean islands of Islay and Colonsay. Demographic studies have shown that a significant factor in the population decline on Islay has been reduced survival from fledging to 1 year of age (juveniles). Understanding the significance of infectious and non-infectious diseases in chough mortality is crucial to the development of successful management strategies aimed at conserving breeding populations of choughs in Scotland and elsewhere.
Postmortem examinations were carried out on 72 choughs found dead or euthanased on welfare grounds on Islay between 2004 and 2024.
Significant burdens of helminths, some not previously recorded in choughs, were found in 18 juvenile choughs (78.3% of all juveniles examined). Genetic eye abnormalities analogous to Peters' anomaly in people were present in 16 nestling/fledgling choughs. Several other infectious and non-infectious causes of death were also found.
The number of carcases examined was only a small sub-sample of all choughs dying on Islay.
Future strategies to conserve choughs on Islay will need to address the underlying causes of the increased losses from helminthiasis in juvenile choughs and assess the implications of inbreeding as demonstrated by the genetic eye disorders.
近年来，苏格兰红嘴山鸦（Pyrrhocorax pyrrhocorax）的繁殖种群数量有所下降，目前所有繁殖对都局限于艾莱岛和科伦赛岛这两个赫布里底群岛。人口统计学研究表明，艾莱岛种群数量下降的一个重要因素是幼鸟从出雏到1岁（幼年期）的存活率降低。了解传染病和非传染病在山鸦死亡中的重要性，对于制定旨在保护苏格兰及其他地区山鸦繁殖种群的成功管理策略至关重要。
对2004年至2024年间在艾莱岛发现死亡或因福利原因实施安乐死的72只山鸦进行了尸检。
在18只幼年山鸦（占所有检查幼鸟的78.3%）中发现了大量寄生虫，其中一些寄生虫此前未在山鸦身上记录过。16只雏鸟/刚离巢的山鸦存在类似于人类彼得斯异常的遗传性眼部异常。还发现了其他几种传染病和非传染病导致的死亡原因。
检查的尸体数量只是在艾莱岛死亡的所有山鸦中的一个小样本。
未来在艾莱岛保护山鸦的策略需要解决幼年山鸦因蠕虫病导致损失增加的根本原因，并评估近亲繁殖如遗传性眼部疾病所显示的影响。
