在英國，入侵物種灰松鼠自19世紀末已一直威脅當地的紅松鼠，除了競爭資源及為紅松鼠帶來致命病毒，同時亦會剝除樹皮破壞樹木。為拯救紅松鼠，科學家計劃將含避孕藥的榛子醬放在只有灰松鼠才能觸及的覓食點，希望能阻止灰松鼠繁殖。

in UK, the invasive grey squirrels have been a threat to the native red squirrels since the late 19th century. They are competing for food and are spreading a fatal virus to the red squirrels. they are also damaging trees through bark stripping. to reduce their population and save the native red squirrels, scientists are planning to place hazelnut spread with contraceptives in feeding spots only the grey squirrels can access. 

https://www.mirror.co.uk/news/uk-news/new-contraceptive-pill-initiative-curb-23417720