荒漠伯劳的繁殖及雏鸟生长发育

2006～2007年对新疆石河子市荒漠伯劳(Lanius isabellinus phoenicuroides)的巢、卵及雏鸟的生长发育状况进行了研究.结果表明,荒漠伯劳窝卵数平均5.67枚,孵卵期17 d,育雏期15 d.育雏主要由雌鸟担任.采用Logistic方程对雏鸟发育过程中主要生长指标的生长方程进行了曲线拟合,相关指标生长方程的拟合度均在0.99以上.     

Diet of the nominate Southern Grey Shrike Lanius meridionalis meridionalis in the north of its range (Mediterranean France)

Capsule In this region the diet is mainly cold-blooded prey, mostly insects such as beetles.

Aims To describe the diet of this newly separated, poorly documented and endangered species.

Method Diet was inferred from pellet analysis, collected during a single breeding and winter period in the steppe of the Crau.

Results A total of 5409 prey were identified from 257 pellets. Vertebrates were seldom taken, except by adults (small passerines) during the fledgling period. High seasonal differences were found. Hymenoptera were largely consumed in autumn, Arachnida in autumn and winter, Orthoptera in summer and autumn and Lepidoptera larvae in winter and spring and by fledglings. Nevertheless, Coleoptera were ingested in large proportions all year round. Carabidae were the main prey in winter and Melolonthidae were especially important for adults during the nestling period, as were Cetoniidae for the fledglings.

Conclusion Small mammals and small birds were less exploited in France and Spain (L. m. meridionalis) than in Israel (L. m. elegans or L. m. aucheri), whereas the opposite might be expected, following a north–south climatic gradient. Thus, the nominate subspecies L. m. meridionalis differed in diet from L. m. elegans or L. m. aucheri.     

Sex differences in nest defence by the red-backed shrike<Emphasis Type="Italic"> Lanius collurio</Emphasis>: effects of offspring age,brood size,and stage of breeding season

The red-backed shrike Lanius collurio is an open-cup nesting passerine bird, which protects its nest aggressively attacking predators near the nest. The response of parents to a human observer was investigated during the nesting period 1999–2001 in Poland. The intensity of nest defence increased as the breeding cycle progressed in accordance to the offspring value hypothesis. However, we did not find an increase in the level of aggression according to the number of offspring and the time of season. Contrary to previous predictions, we did not find gender differences in nest defence. More aggressive parents, both females and males, have significantly better breeding success than quieter individuals.     

Sexual size dimorphism and positive assortative mating in red-backed shrike Lanius collurio: an adaptive value?

During field studies in 1997–1999 in South Bohemia (Czech Republic), we found significant differences in size between the sexes in a local breeding population of red-backed shrike Lanius collurio. Males were significantly larger than females for wing length and tarsus length, but had smaller body mass than females. However, there was considerable overlap in the ranges of these parameters between the sexes. Interestingly, pairs were formed at random with respect to wing length and tarsus length, but assortative mating was significant for body mass/body condition. Among tested variables, only male wing length correlated significantly with nestling body mass at day 7. However, clutch size and the number of fledglings strongly depended on differences in tarsus length between mates, but not on body size of mates. Individual improvements in foraging skills and/or courtship feeding rates are proposed as possible explanations for these findings.     

Some effects of inclement weather conditions on the survival and condition of bull-headed shrike nestlings

Inclement weather struck Japan in 1993, permitting a natural experiment for examining the effect of weather conditions on nesting success and nestling growth of the bull-headed shrike, Lanius bucephalus. Aspects of the breeding biology of bull-headed shrikes in relation to weather conditions and timing of breeding in 1992 and 1993 were examined. The two breeding seasons were divided into two periods, early and late, in each year. While the probability of nest survival in nestling stages during both periods was almost equal, the probability of nest survival in the egg stage during the early period was significantly lower than that during the late period. In 1993, the probability of nestling survival during the late period was significantly lower than during the early period; the late period had larger fluctuations of precipitation and was colder than the same period in 1992. The number of disappeared nestlings positively correlated with mean precipitation per day. The greater part of the disappeared nestlings was the lightest in each brood. Late breeders fledged lighter young than the early breeders. Although shrikes adopted hatching asynchrony, the late breeders could not surmount the unpredictable inclement weather in 1993.     

Phylogeography of the fiscal shrike (Lanius collaris): a novel pattern of genetic structure across the arid zones and savannas of Africa

Aim Savanna occupies a substantial part of Africa, being distributed around the two major tropical rain forest blocks in what is referred to as the Savanna Belt. Our current understanding of the genetic structure within species distributed across the Savanna Belt is primarily derived from mammalian taxa, studies of which have revealed a suture zone or transition between northern and east/southern Africa clades in south‐western Kenya and north‐western Tanzania. We conduct a phylogeographic study of the fiscal shrike (Lanius collaris), a polytypic species distributed across the Savanna Belt of Africa and for which morphological and vocal data are in agreement with the suture zone recovered for mammalian taxa, to test the hypothesis of a spatially congruent genetic break across several taxa, including birds. Location Africa, south of the Sahara. Methods We analysed DNA sequences recovered from four loci (one mitochondrial, two autosomal and one Z‐linked) in 66 individuals, representing all recognized subspecies, as well as putatively closely related species. We make use of a combination of tree‐building and population genetic methods to investigate the phylogeographic structure of the fiscal shrike across Africa. Results The fiscal shrike consists of two primary lineages with a strong geographic component: a northern group distributed from southern Tanzania to Senegal, and a southern group distributed from Botswana/Zambia to South Africa with isolated populations in Tanzania and northern Malawi. Unexpectedly, Souza’s shrike (L. souzae) was nested within L. collaris, as the sister group of the southern group. The positions of Mackinnon’s shrike (L. mackinnoni) and that of the São Tomé shrike (L. newtoni) were variable, being either nested within the fiscal shrike or sister to the L. collaris–L. souzae clade. Our divergence time analyses suggest that the Lanius collaris species complex started to diversify around 2.2 Ma. Main conclusions Our study reveals a distinct biogeographic pattern for a savanna distributed species in Africa, with the transition between the two primary genetic lineages occurring at a latitude of c. 15–16° S, 10° S further south than shown elsewhere for several mammalian species.     

四川南充地区棕背伯劳繁殖期鸣声的初步研究

2008年3～8月,对四川南充地区棕背伯劳繁殖期鸣声进行了初步的研究.研究期间共记录到430次棕背伯劳的鸣声.根据对其行为和鸣声波谱图、语谱图特点的分析,繁殖期棕背伯劳的鸣声可分为:占区、驱逐、求偶、幼鸟乞食、召唤和应答6种叫声,对棕背伯劳繁殖期鸣声的特点进行了分析讨论.     

Composition and diversity of bird communities in Swedish farmland–forest mosaic landscapes

CapsuleThe amount of forest (at local and landscape scales) and occurrence of residual habitats at the local scale are shown to be the major factors influencing bird community composition in farmland–forest landscapes in central Sweden.

Aims To investigate the importance of local habitat and landscape structure for breeding birds in farmland–forest landscapes in central Sweden.

Methods Breeding birds were censused at 292 points. A detailed habitat mapping was made within 300 m of the points. Within a 300–600 m radius only two major habitats (forests and arable fields) were identified.

Results Cluster analyses of bird communities identified three site types that also differed in habitat composition: (i) partially forested sites in forested landscapes; (ii) heterogeneous sites with residual habitats in mosaic landscapes; and (iii) field-dominated farmland sites in open landscapes. A total of 19 of 25 farmland bird species (restricted to farmland or using both farmland and forest) had the highest abundance in farmland sites with mosaics of forest and farmland, while only six farmland species had the highest abundance in field-dominated sites. The bird community changed from being dominated by farmland species to being dominated by forest species (common in forest landscapes without farmland) at small proportions (10–20%) of forest at the local scale. A major difference in habitat composition between heterogeneous and field-dominated sites was the occurrence of different residual habitats (e.g. shrubby areas and seminatural grasslands). These habitats seemed to influence bird community composition more than land-use, despite covering <10% of the area. Seminatural grasslands were important for bird community composition and species-richness, but grazing seemed to be less important. Among different land-use types, cereal crops were the least preferred fields. Set-asides with tall vegetation and short rotation coppices were positively associated with species-richness of farmland birds.

Conclusion In general, the composition of the landscape was important for bird community composition, although amount and distribution of forests, occurrence of residual habitats and land-use of fields at the local scale had the strongest influence on bird community composition. The possible implications of these patterns for managing farmland–forest landscapes are discussed.     

Observer variation in estimates of Meadow Pipit Anthus pratensis and Skylark Alauda arvensis abundance on moorland

Capsule Counts least susceptible to observer effects were those within 25 m of a transect and the total number along a transect, with observer effects greater for distance sampling.