Millán J, Gortázar C, Tizzani P, Buenestado F J
Instituto de Investigación en Recursos Cinegéticos (IREC, CSIC-UCLM), PO Box 535, E-13080 Ciudad Real, Spain.
J Helminthol. 2002 Sep;76(3):225-9. doi: 10.1079/JOH2002125.
The success of ring-necked pheasant (Phasianus colchicus) restocking in Asturias, northern Spain was assessed, and the role of parasites and predators in the mortality of released birds was studied. The experimental release of 56 radio-tagged pheasants showed that 98% of birds died within 12 days. As soon as 72 h after release, 67.5% of males and 55.0% of females were found dead. Foxes (Vulpes vulpes) killed 63% of the birds. The survival of those birds killed by foxes was lower than for birds which died due to other causes, and pheasants depositing eggs of the nematode Eucoleus contortus (Creplin, 1839) survived less than those apparently non-parasitized. No impact of the parasite on the pheasants' condition was found, but foxes preyed upon parasitized birds more than expected by random. The results suggest that: (i) the current pheasant releases in this area are unsuccessful and need to be improved; (ii) this is mainly due to intense predation by red foxes; and (iii) parasites could have some influence on the predation of released birds by foxes. However, the way parasites affect pheasant vulnerability remains unclear.
对西班牙北部阿斯图里亚斯环颈雉（Phasianus colchicus）重新引入的成功情况进行了评估，并研究了寄生虫和捕食者在放归鸟类死亡中所起的作用。对56只带有无线电标签的雉鸡进行的实验性放归表明，98%的鸟类在12天内死亡。放归后72小时内，就发现67.5%的雄性和55.0%的雌性死亡。狐狸（Vulpes vulpes）杀死了63%的鸟类。被狐狸杀死的鸟类的存活率低于因其他原因死亡的鸟类，且产卵有捻转毛细线虫（Creplin，1839）的雉鸡的存活时间短于那些显然未被寄生的雉鸡。未发现寄生虫对雉鸡状况有影响，但狐狸捕食被寄生鸟类的情况比随机预期的更多。结果表明：（i）该地区目前的雉鸡放归是不成功的，需要改进；（ii）这主要是由于赤狐的强烈捕食；（iii）寄生虫可能对狐狸捕食放归鸟类有一定影响。然而，寄生虫影响雉鸡易感性的方式仍不清楚。
