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Invasive Deer Threaten Native Red Deer Survival
11 Jan
Summary
- Sika deer population boomed 10% while red deer declined 22%.
- Sika deer are smarter, more fertile, and adaptable than native red deer.
- Experts warn culls must target invasive sika to protect red deer.
Invasive sika deer are posing a significant threat to the survival of native red deer populations across Britain, according to new research. A study published in Ecological Solutions and Evidence highlights that sika deer, introduced from East Asia in the 19th century, are experiencing a population surge while native red deer struggle. Analysis from Scottish estates showed sika numbers increased by 10% in 2024-25, contrasting with a 22% decline in red deer, despite overall culling efforts.
Experts point to several advantages possessed by sika deer, including superior intelligence, higher fertility rates, and remarkable resilience to poor environmental conditions and limited food resources. They can also thrive in higher densities that would stress native species. These traits, combined with their ability to adapt quickly and a tolerance for parasites, make them formidable competitors. Furthermore, the potential for hybrid offspring between sika and red deer could introduce further competitive advantages, imperiling native deer survival.
Researchers warn that current deer management strategies, which often involve culling all species indiscriminately, may inadvertently favor the invasive sika. This approach risks a scenario where landscapes become dominated by sika, similar to the impact of grey squirrels on red squirrels. A focused, species-specific culling strategy is urgently needed to protect native red deer and prevent their decline.
