A new Danish genetic study has found no hybrids between sika deer and native red deer, undercutting the main argument behind the plan to eradicate Denmark’s roughly 2,100 sika deer. The report is now landing on the desk of Nature and Animal Welfare Minister Christian Rabjerg Madsen.
DR reports that the report is being presented to the minister as culling of sika deer is already under way. The species became the subject of a heated nature policy debate after the EU declared it invasive last year. Under the rules as they stand, all sika deer in Denmark are to be removed.
Senior researcher Niels Tommerup of the University of Copenhagen carried out a chromosome analysis comparing DNA from both species across the country. According to DR, he concludes that interbreeding does not happen, and that it would be very rare if it did. The study used blood samples from 56 sika deer and 22 red deer, making it among the most extensive of its kind worldwide.
The project was initiated by veterinarian Astrid Ingstrup, who collected samples with colleague Flemming Thune-Stephensen and around 100 volunteer hunters, forest owners and deer park staff. Dansk Skovforening, which financed the laboratory work, stated in January 2026 that the study was launched after the EU listing in order to clarify the actual risk in Denmark.
In Jægersborg Dyrehave north of Copenhagen, half of the sika population has already been shot, and the rest will be culled within weeks. Naturstyrelsen announced in December 2025 that about 140 animals would be shot there. Elsewhere, males are to be shot this autumn to prevent new calves.
Authorities cite a precautionary principle
The Styrelsen for Grøn Arealomlægning og Vandmiljø stated in December 2025 that sika deer must be phased out, including fenced herds, to avoid a hybrid population with red deer. Senior adviser Morten Elmeros of Aarhus University, who has advised the agency, maintains his position. Per DR, he calls the genetic dilution seen in Scotland and Ireland an irreversible process.
Ingstrup points to a difference in size between Danish and British Isles deer, arguing that Danish sika struggle to mate with the much larger red deer. She notes that sika make up 0.4 percent of Denmark’s total deer population. Dansk Skovforening director Anders Frandsen calls a full cull a drastic step and suggests monitoring for hybridisation instead.
Danmarks Jægerforbund informed members in January 2026 that hybridisation has not been documented in Denmark, while noting that the risk is the EU’s main concern. Nordjyske reported that Denmark voted against the listing but must still implement it.
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