The barred owl (Strix varia) invasion in California
The barred owl (Strix varia) invasion in California
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作者：
Dark, SJ;Gutierrez, RJ;Gould, GI
我们估计了加州条纹猫头鹰 (Strix varia) 的活动范围扩大以及该物种可能对斑点猫头鹰 (Strix occidentalis) 产生的潜在负面影响。在过去的二十年里，斑纹猫头鹰的活动范围迅速扩大。加州 12 个不同县总共发现了 61 只斑纹猫头鹰。条纹猫头鹰于 1981 年首次在加利福尼亚州德尔诺特县和三一县被发现。现在南至加利福尼亚州西部的索诺玛县和内华达山脉的尤巴县都发现了它们。每个新斑点猫头鹰领地发现的新条纹猫头鹰栖息地的比例已从 20 世纪 80 年代每 50 个斑点猫头鹰领地 1 个增加到 1990 年代中期每 10 到 20 个新斑点猫头鹰领地 1 个。这表明加利福尼亚州的条纹猫头鹰数量正在增加。此外，加利福尼亚州还报告了七只条纹猫头鹰与斑点猫头鹰的杂交种。由于杂交、食物和栖息地竞争以及捕食的可能性，条纹猫头鹰似乎会对斑点猫头鹰种群产生负面影响。
We estimated the range expansion of Barred Owls (Strix varia) in California and the potential negative effects this species may have on Spotted Owls (Strix occidentalis). Barred Owl range expansion has been rapid over the past two decades. A total of 61 Barred Owls has been detected in 12 different California counties. Barred Owls were first sighted in California in 1981 in Del Norte and Trinity counties. They now have been detected as far south as Sonoma County in western California and Yuba County in the Sierra Nevada. The ratio of new Barred Owl sites found per new Spotted Owl territory has increased from one per 50 Spotted Owl territories in the 1980s to one per 10 to 20 new Spotted Owl territories in the mid 1990s. This suggests that the Barred Owl population in California is increasing. In addition seven Barred Owl x Spotted Owl hybrids have been reported in California. Because of the potential for hybridization, competition for food and habitat, and predation, it appears that the Barred Owl could influence Spotted Owl populations negatively.