Function of courtship feeding in the Bull-headed Shrike,Lanius bucephalus

We investigated the frequency of courtship feeding (CF) in the Bull-headed Shrike (Lanius bucephalus) during the 1981–1982 breeding seasons. Because no CF was observed just prior to, during or just after copulation, CF is not associated directly with copulation and does not function as a releaser for copulation. The absence of CF during the pair-formation period of the early breeder and the high frequency of CF behavior in the cold season and in the critical breeding stages (egg-laying and incubation stages) for females strongly suggests that the significance of CF in this species is not symbolic but substantial at least in early breeders. We assign one of the causes of this CF to the early onset of breeding.     

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     

棕背伯劳的雏鸟生长和出飞后行为发育的初步观察

2005年3-5月对南充地区棕背伯劳（Lanius schach）雏鸟的生长进行了观察和测量,并对出飞之后的行为发育进行了初步研究。结果表明,棕背伯劳育雏期12～13d,观察21雏成活18只,成活率为85．7％。体重、体长和其他形态特征的生长都适用于Logistic方程拟合。出飞后笼养雏鸟的“理翅羽”和“一侧翅下展,同时同侧脚下伸”行为频率最高,分别为18．81％和11．88％。     

黑龙江省发现棕尾伯劳

高峰鸟类保护环志站2002年5月28日环志时,捕到一只伯劳,其大小、羽色、形态酷似红尾伯劳,但它具白色翅斑,尾羽橙棕色(锈红色)至棕褐色(图版,封4)。2006年1月,经郑光美院士鉴定,该鸟为棕尾伯劳Lanius isabellious。量度见表1。表1棕尾伯劳的环志号码和量度环志号码性别鸟体量度(mm)头喙喙长翅长体长尾长跗C06-2953♂40·0 15·0 87·0 188·0 85·0 28·0棕尾伯劳,又名荒漠伯劳。隶属雀形目伯劳科。本次捕到的是一只雄鸟,上体灰褐,尾羽棕红色,翼上有白斑,飞行时很明显。过眼纹黑色(但无眼先带);眉纹白;虹膜褐色;嘴灰色;脚深灰。鸣声丰富多变…     

虎纹伯劳的巢生境选择与繁殖行为

2005年3~7月通过焦点动物取样法(focal animal sampling)和完全记录法(all-occur rencerecording)对四川南充地区虎纹伯劳的繁殖行为进行了研究。结果表明,虎纹伯劳喜在5~12m的高大阔叶乔木的冠部分叉处营巢。对15个巢址主成分分析表明,前5个主成分特征值均大于1,累积贡献率高达83.15%,说明前5个主成分已经基本包含了所有参数的总信息量。4月下旬开始陆续有虎纹伯劳迁到,初到时并未配对。5月上旬开始出现求偶行为,并伴有递食行为。5月中旬首次见到营巢,两性参与营巢,营巢期5~7d。营巢结束一两天后开始产卵,一天一枚,窝卵数4~6枚。营巢期和产卵期都有求偶和交配行为。产完最后1枚卵后即开始由雌鸟单独孵卵,孵卵期13~14d。两性育雏,育雏期13~15d。     

Seasonal change in Red-backed Shrike Lanius collurio territory quality - the role of nest predation

This paper examines the relationships between territory preference, reproductive performance and nest predation in a Red-backed Shrike Lanius collurio population breeding in rapidly changing farmland. Territory preference was measured by (a) the order of laying dates in territories within years and (b) territory occupation frequency over a five-year period. Seven environmental variables were tested but only the density of Sloe (Blackthorn) Prunus spinosa in territories was correlated positively with territory occupation frequency. Within years, Red-backed Shrikes started to breed earlier in territories with more Sloe, but reproductive performance was not related consistently to territory differences. A high proportion of Sloe-rich territories was vacant each year. Thus, the observed negative association between settlement order and amount of Sloe may reflect a seasonal change in habitat preference. Early breeders prefer Sloe-rich territories whereas late birds prefer Sloe-poor territories. Supporting evidence is that the proportion of occupied territories that was Sloe-rich was higher for early than for average or late first breeding attempts. Moreover, in contrast to early in the season, the probability of a replacement clutch following nest failure was not associated with the amount of Sloe, but increased with increasing densities of Juniper Juniperus communis. Late in the nesting season, pairs breeding in Sloe-rich territories suffered higher nest predation than those breeding in Sloe-poor territories. In early nesting attempts, however, the relationship was reversed. Nest predation is probably an important selective agent on habitat selection since it was the principal factor explaining variation in the numbers of fledglings produced among territories. Thus, the Red-backed Shrike may shift territorial preferences adaptively as the season progresses to match within-season changes in predation pressure in different types of territories.     

Behaviour and breeding biology of the cooperatively breeding Grey-backed Fiscal Shrike Lanius excubitorius in Kenya

Grey-backed Fiscal Shrikes Lanius excubitorius were studied over a 2j year period near Lake Naivasha, Kenya. Grey-backs are cooperative breeders, with group sizes ranging from two to II. Only one pair breeds per group, with all other group members aiding in the rearing of young. The study population ranged from 64 to 79 individuals that occurred in from 13 to 16 groups. Non-breeding helpers made up to 66% of the population, with male helpers being more numerous overall than females. The annual survival rate was 65%, with no differences detected between the survival of males and females, or of breeders and helpers. Only male helpers were observed to acquire breeding status within the natal territory. Some female helpers acquired breeding positions in territories adjacent to their natal territories. Group territorial displays occurred throughout the year but were most pronounced prior to breeding during rainy periods. Reproductive success was very low, with only 14.5% of the recorded breeding attempts leading to fledged young. Large groups (four or more birds) had greater reproductive success than small groups, but many factors other than, or in addition to, group size may have influenced this pattern. The breeding male contributed the most food to the incubating female and to the nestlings. Male helpers and the breeding female contributed more to nestlings than did female helpers. Observations on the post-fledging period indicate that socialization and establishment of dominance may be of importance in group-living species living in a restricted ecological and social setting.     

Storing prey in larders affects nestling haematological condition in the Red-backed Shrike (Lanius collurio)

Many animals, including shrikes (Laniidae), are known to store food. This behaviour ensures food availability during inclement weather, for rearing nestlings or signalling territory quality. Unlike most other shrike species, which accumulate food before breeding, Red-backed Shrikes Lanius collurio store food in larders, mainly during the nestling and fledgling periods. If this is an adaptive behaviour, variation in this behaviour should affect either or both the number and condition of nestlings, which may benefit from such larders. We assessed the haematological condition of Red-backed Shrike nestlings in east-central Poland in 2021 using a suite of blood parameters relating to sites where shrikes did or did not store food. Haemoglobin concentrations were positively correlated with larders, being significantly higher in nestlings of pairs that stored prey compared with those whose parents did not do so. White blood cell counts were lower in nestlings whose parents kept larders. Red blood cell counts and glucose concentrations in nestlings were not related to whether parents had larders. Food storage probably ensures a more constant access to food, which results in a superior haematological condition in nestlings.     

Moult in the Loggerhead Shrike Lanius ludovicianus is influenced by sex,latitude and migration

We investigated moult strategies in Loggerhead Shrikes by examining first prebasic or preformative moult patterns and by assessing the general location where individual feathers were grown using stable hydrogen isotope (δ²H) analysis. We tested the relative importance of factors known to impact moult timing and pattern, including age, sex, body size, food availability and migration. Migratory Shrikes showed evidence of suspended moult, in which feathers are moulted on both the breeding and the non‐breeding grounds with a suspension of moult during migration. Extent of moult was best explained by sex, longitude, migratory behaviour and breeding‐ground latitude. Male Hatch Year (HY) Shrikes replaced more feathers on the breeding grounds prior to migration than did HY females and moulted more extensively on the breeding grounds than did females. Non‐migratory HY Shrikes underwent a more extensive preformative moult than migratory HY Shrikes. Individuals in more southerly migratory populations moulted more extensively on the breeding grounds than did those breeding further north. Our data also indicate that individuals in the northeastern populations moulted more extensively on the breeding grounds than did those in the north and southwest. Our study underlines the complex structure and variation in moult possible within species, revealing surprising levels of differentiation between sexes and age cohorts, linked to environmental factors on the breeding grounds. Our study highlights the utility of an intrinsic marker, specifically δ²H analysis, to test hypotheses regarding the evolutionary and ecological forces driving moult. Although the methodology has not commonly been applied to this area of research, our results indicate that it can provide unprecedented insight into inter‐ and intra‐specific adaptive response to constraints, whereby individuals maximize fitness.     

Population decline is accompanied by loss of genetic diversity in the Lesser Grey Shrike Lanius minor

The Lesser Grey Shrike has suffered successive declines in population size and a marked contraction of its breeding range since the early 20th century, largely because of long‐term agricultural intensification. This has resulted in a severely fragmented distribution in Western Europe, with isolated breeding nuclei in Spain, France and Italy and a more continuous distribution in Eastern Europe and Asia. Using a combination of nuclear and mitochondrial markers, we assessed the genetic structure and diversity of Lesser Grey Shrike populations from Western Europe, Central Europe and Asia. There was significant genetic differentiation among three major regional groups, one European and two Asian. Genetic diversity measures were lowest in the smallest and most marginal Spanish population. Limited genetic diversity, combined with rapid population decline, suggests the Spanish population may face extinction in the near future.     

Dummy birds in artificial nest studies: an experiment with Red-backed Shrike Lanius collurio

Capsule Dummy birds placed on artificial nests increase nest survival, and their use should be considered in future studies of nest predation.     

荒漠伯劳的递食位置与同胞竞争

亲鸟递食位置可以调控雏鸟之间的竞争,而异步孵化会使不同孵出顺序雏鸟的体况产生等级差异。雏鸟可以通过竞争巢中有利位置来获得更多的食物资源,从而提高自身生长发育速度和存活率。本研究于2013和2014年两年的4至8月对甘肃安西荒漠保护区桥子片区22巢荒漠伯劳(Lanius isabellinus)的递食行为进行研究。结果发现,荒漠伯劳亲鸟递食的位置主要集中在1个(n=13,比例超过50%)或2个(n=9,合并比例超过60%)位置上,具有一定的可预测性;处于亲鸟递食位置直线方向上的雏鸟获食次数显著高于两侧位置(n=22,P <0.001)。但异步孵化雏鸟的孵出顺序与其在巢内占据直线(df=4,F=0.211,P> 0.05)和两侧位置(df=4,F=0.068,P> 0.05)的次数都不具相关性;并且不同孵出顺序雏鸟间平均获食次数无明显差异(df=4,F=0.090,P> 0.05);拟合不同孵出顺序的雏鸟生长曲线发现,不同孵出顺序雏鸟的体重生长率也没有表现出明显差异(df=4,F=0.637,P>0.05)。研究结果表明,荒漠伯劳亲鸟趋于固定递食位置并向直线方...     

Breeding biology and breeding success of the Lesser Grey Shrike Lanius minor in a stable and dense population

The Lesser Grey Shrike Lanius minor is highly endangered throughout Europe, having declined markedly in abundance and range. Long-term changes in climate and agricultural practices have been identified as the main reasons for its decline. To determine which factors influence short-term changes in breeding success, we examined several aspects of its breeding biology. Our investigation revealed that our study area bears a large and stable population of this species. In 1996 and 1997, we recorded 84 and 77 breeding pairs in an area of 20 km², with an average of 4.20 and 3.85 pairs/km² respectively. Data on breeding density, clutch size and fledging success from 1989 to 1997 (excluding 1992) indicate a stable breeding population with a constant high breeding success. Reproductive success declined through the season, mainly through seasonal variation in clutch size rather than chick mortality. However, breeding success was generally high (69% and 79% of the nests produced chicks], with low hatching failure and few nest losses. The main cause of breeding failure was nest predation (at least 50% of nest losses), mainly by magpies (at least 66% of depredated nests). Although in this population the Lesser Grey Shrike tends to aggregate in clusters, breeding density had no obvious effect on breeding success and nest predation.     

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.     

Hatching order and sex ratio in Southern Grey Shrike Lanius meridionalis in relation to clutch size

Despite major advances in sex ratio theory, how offspring sex should vary with hatching order remains unclear. We examine nestling sex ratio in the Southern Grey Shrike Lanius meridionalis according to hatching order and clutch size. Southern Grey Shrike nestlings present a different sex ratio with body‐mass rank order depending on clutch size. When the clutch size was five eggs (with a very low risk of brood reduction; 13%) the less costly sex (male) was found at the end of the body mass hierarchy. However, when clutch size was six eggs (with a high risk of brood reduction; 42%) the larger sex (female) was found at intermediate positions in the hatching order, possibly to decrease competitive asymmetries.     

Benefits of Extra Begging Fail to Compensate for Immunological Costs in Southern Shrike (Lanius meridionalis) Nestlings

Theoretical models aimed at explaining the evolution of honest, informative begging signals employed by nestling birds to solicit food from their parents, require that dishonest signalers incur a net viability cost in order to prevent runaway escalation of signal intensity over evolutionary time. Previous attempts to determine such a cost empirically have identified two candidate physiological costs associated with exaggerated begging: a growth and an immunological cost. However, they failed to take into account the fact that those costs are potentially offset by the fact that nestlings that invest more in begging are also likely to obtain more food. In this study, we test experimentally whether a 25% increase in ingested food compensates for growth and immunological costs of extra begging in southern shrike (Lanius meridionalis) nestlings. Three nestmates matched by size were given three treatments: low begging, high begging-same food intake, and high begging-extra food intake. We found that, while a higher food intake did effectively compensate for the growth cost, it failed to compensate for the immunological cost, measured as T-cell mediated immune response against an innocuous mitogen. Thus, we show for the first time that escalated begging has an associated physiological net cost likely to affect nestling survival negatively.