Summer diet of two sympatric species of raptors Upland Buzzard (Buteo hemilasius) and Eurasian Eagle Owl (Bubo bubo) in alpine meadow: problem of coexistence

Summer diets of two sympatric raptors Upland Buzzards (Buteo hemilasius Temminck et Schlegel) and Eurasian Eagle Owls (Bubo bubo L. subsp. Hemachalana Hume) were studied in an alpine meadow (3250 m a.s.l.) on Qinghai-Tibet Plateau, China. Root voles Microtus oeconomus Pallas, plateau pikas Ochotona curzoniae Hodgson, Gansu pikas O. cansus Lyon and plateau zokors Myospalax baileyi Thomas were the main diet components of Upland Buzzards as identified through the pellets analysis with the frequency of 57, 20, 19 and 4%, respectively. The four rodent species also were the main diet components of Eurasian Eagle Owls basing on the pellets and prey leftovers analysis with the frequency of 53, 26, 13 and 5%, respectively. The food niche breadth indexes of Upland Buzzards and Eurasian Eagle Owls were 1.60 and 1.77 respectively (higher value of the index means the food niche of the raptor is broader), and the diet overlap index of the two raptors was larger (C-ue = 0.90) (the index range from 0 - no overlap - to I - complete overlap). It means that the diets of Upland Buzzards and Eurasian Eagle Owls were similar (Two Related Samples Test, Z = -0.752, P = 0.452). The classical resource partitioning theory can not explain the coexistence of Upland Buzzards and Eurasian Eagle Owls in alpine meadows of Qinghai-Tibet Plateau. However, differences in body size, predation mode and activity rhythm between Upland Buzzards and Eurasian Eagle Owls may explain the coexistence of these two sympatric raptors.

平面几何问题解决过程中的元认知实验研究

This study was based on the cognitive-metacognitive model of mathematical problem solving established by Lester & Garofalo(1985). The method of protocal analysis was used and 19 excellent students(9 male and 10 female) & 19 learning-disabled students(11 male and 8 female) in middle school(grade 3)were tested and interviewed during they solved plane geometry problems. The main results showed as follows: (1) There was a significant difference between excellent students and learning-disabled students on time-assignment when they solved plane geometry problems. Excellent students used more time on phase organization and less time on phase execution. There was no difference on phases orientation and verification. (2) Excellent students showed higher metacognitive level than learning-disabled students. The deference existed in phases orientation and organization. Excellent students reported more metacognitive sentences in phases orientation and organization than learning-disabled students. They had more self-awareness and goal-awareness. They had more "knowledge about what they know" and "knowledge about what they should use". They designed more globle goal and subgoals and made more self-evaluation. (3) Both the excellent students' and learning-disabled students' self-checking level should be improved.