四川攀枝花发现栗背伯劳

<正>2014年4月17日上午7:20时许,在攀枝花市西区格里坪镇竹林坡村(26°38′42.26″N,101°31′34.61″E,海拔1 991 m)的山坡农田边缘低矮灌丛中,观察并拍摄到一只伯劳(图1)。该鸟头顶黑灰色,到枕部转为灰色,前额、眼先、眼周和耳覆羽深黑色,形成粗而明显的贯眼纹。喉、胸及下体白色。肩、背为深栗色。尾羽黑色,但外侧尾羽为白色。飞羽为黑色,但具有褐色羽缘,且在大覆羽下方有一白色翅斑。确认为雄性栗背伯劳(Lanius     

Risk-taking behavior of bull-headed shrikes that recently colonized islands

Individuals which have invaded urbanized environments are reported to engage in riskier behaviors, possibly influenced by the scarcity of predators in urbanized areas. Here, we studied the risk-taking behavior of birds which had invaded a new natural environment, rather than an artificial urban environment, using recently established populations of the bull-headed shrike Lanius bucephalus, which naturally colonized three subtropical islands in Japan. We compared flight initiation distance (FID), the distance at which an individual approached by a human initiates flight, between the islands and the temperate mainland. FID was longer for the insular shrikes compared with the mainland shrikes after controlling for other factors, indicating that the individuals which had invaded a new natural environment had a lower propensity for risk-taking. A possible explanation for these results is that low risk-taking behavior might be adaptive on the islands due to predation by the black rat Rattus rattus, an unfamiliar predator not found in shrike habitats on the temperate mainland. Further studies are needed to examine the nest predation rate, predator species, and nest site selection of these insular shrike populations.     

Long-term trends in the timing of breeding and brood size in the Red-Backed Shrike Lanius collurio in the Czech Republic, 1964–2004

Climate change has affected breeding dates and clutch sizes in many bird species. To date, most of the studies aimed at assessing the effects of climate change on these phenological events in birds have been on hole-nesting species and the changes linked either to local climate variation or to some large-scale composite variables, such as the North Atlantic Oscillation (NAO). Relatively less is known about the climate responses of open-nesting birds and on the relative roles of climate variables at different scales. Using bird ringing records covering a time span of 41 years, we documented shifts in the timing of breeding and brood size in a long-distance migrant, the Red-Backed Shrike (Lanius collurio) from a central European population. We found a 3- to 4-day shift towards earlier breeding and an increase in brood size by approximately 0.3 nestlings since 1964. The Red-Backed Shrikes start to breed in May and rear the first nestlings in June. During the period 1964–2004, temperatures in May significantly increased, while the increase in June temperatures was not significant. Simultaneous tests on the influence of local climate variables and the NAO index revealed a better performance of local climate. The increasing temperature in May was positively associated with the advancement of breeding. Similarly, at a local scale, higher May temperatures were followed by larger brood sizes, while a high amount of rainfall had a strong negative effect.