Avian predation on wild and cultured sea urchin <Emphasis Type="Italic">Strongylocentrotus intermedius</Emphasis> in a rocky shore habitat

ABSTRACT:   The present study reports the annual variation in consumption of the sea urchin Strongylocentrotus intermedius by avian predators on a rocky shore where the culture of sea urchins has been conducted. Carrion crow and a few gull species were the most abundant avian predators and consumed a large number of sea urchins. Crows consumed mostly natural sea urchins, approximately 36 kg ww/ha per year on the intertidal rocky bench, but the gull species consumed mostly cultured sea urchins, approximately 100 kg ww/ha per year in the culture area. The seasonal variation in the amount of sea urchins consumed by crows was higher than that by the gull species, presumably because of the difference in foraging behavior in association with the seasonal tidal cycle. The natural sea urchins consumed are an allochthonous input from the subtidal to the intertidal habitat, and thus, crow predation may not affect the natural and the cultured populations of the sea urchin. The gull species consumed much of the cultured sea urchin, and thus, may be regarded as an effective predator causing damage to sea urchin culture. The results suggest that further studies are needed to determine why the gull species selectively feed on cultured sea urchins.     

Molecular sexing of Jungle crow (Corvus macrorhynchos japonensis) and Carrion crow (Corvus corone corone) using a feather

A molecular sexing method using the intron‐size difference between chromo‐helicase‐DNA binding protein (CHD1) genes on the Z and W sex chromosomes (CHD1Z and CHD1W, respectively) was developed for wild Jungle crows and wild Carrion crows. The polymerase chain reaction product sizes were 661 bp for CHD1Z and 465 bp for CHD1W in both the Jungle and the Carrion crows. Each male crow sample produced a single fragment (CHD1Z), whereas female samples produced two fragments (CHD1Z and CHD1W), which differed by 200 bp in crows. In the present study, sexing live Jungle and Carrion crows was performed by applying the method to a feather for molecular sexing.     

Gross morphological features of the air sacs of the hooded crow (Corvus cornix)

Air sacs are considered to be one of the controlling factors of bird behaviour and habits in addition to their roles in ventilation, regulating body temperature, swimming and flight. As a scavenger and an omnivorous flight bird, air sacs of the hooded crow were the focus of this study. Eight healthy, adult hooded crows were used to examine the morphological characteristics of the air sacs, which were examined grossly and with latex and cast preparations. In general, the morphological overview of the hooded crow air sacs is similar to other avian species. We observed nine air sacs; four paired sacs (cervical, cranial thoracic, caudal thoracic and abdominal air sacs) and one unpaired sac; the clavicular air sac. The cervical air sac communicated to the lung through the medioventral bronchus and had three diverticula; intermuscular, subscapular and subcutaneous. The clavicular air sac communicated with lung through the medioventral bronchus and had subscapular, axillary, humeral, subpectoral and sternal diverticula. The cranial and caudal thoracic air sacs were communicated with lung through the lateroventral bronchi and the both sacs did not have any diverticula. The abdominal air sacs were posterior to the caudal thoracic air sacs. The left abdominal sac was the largest air sac. The right and left abdominal sacs gave off branches to diverticula that pneumatized synsacrum. The abdominal air sacs gave off femoral diverticula behind the hip joint as well as perirenal diverticula.     

Corvid response to human settlements and campgrounds: Causes, consequences, and challenges for conservation

Human development often favors species adapted to human conditions with subsequent negative effects on sensitive species. This is occurring throughout the urbanizing world as increases by generalist omnivores, like some crows and ravens (corvids) threaten other birds with increased rates of nest predation. The process of corvid responses and their actual effects on other species is only vaguely understood, so we quantified the population response of radio-tagged American crows (Corvus brachyrhynchos), common ravens (Corvus corax), and Steller’s jays (Cyanocitta stelleri) to human settlements and campgrounds and examined their influence as nest predators on simulated marbled murrelet (Brachyramphus marmoratus) nests on Washington’s Olympic Peninsula from 1995 to 2000. The behavior and demography of crows, ravens, and jays was correlated to varying degrees with proximity to human development. Crows and ravens had smaller home ranges and higher reproduction near human settlements and recreation. Annual survival of crows was positively associated with proximity to human development. Home range and reproduction of Steller’s jays was independent of proximity to human settlements and campgrounds. Local density of crows increased because home ranges of neighboring breeding pairs overlapped extensively (6× more than ravens and 3× more than Steller’s jays) and breeders far from anthropogenic foods traveled 10s of kilometers to access them. Corvids accounted for 32.5% of the predation events (n = 837) we documented on artificial murrelet nests. Small corvids (jays) were common nest predators across our study area but their contribution as predators did not vary with proximity to settlements and campgrounds. In contrast, large corvids (crows and ravens) were rare nest predators across our study area but their contribution varied greatly with proximity to settlements and campgrounds. Managers seeking to reduce the risk of nest predation need to consider the varied impacts and variable behavioral and population responses of potential nest predators. In our situation, removing large corvids may do little to reduce overall rates of nest predation because of the diverse predator assemblage, but reducing anthropogenic food in the landscape may be effective.     

山西芦芽山自然保护区星鸦的繁殖生态

2007～2009年,在山西芦芽山国家级自然保护区对星鸦的繁殖生态进行了研究,结果表明：在本区星鸦主要分布在海拔1 500～2 500 m的针叶林或针阔混交林带;繁殖前3月的种群密度为0.25只/km,繁殖后的8月种群密度为0.43只/km;繁殖期为4～7月,最早产卵期为4月19日,窝卵数为3～5枚,孵化期为17～18 d,孵化率为83.2%,巢内育雏期18～19 d,幼乌离巢率为96%;星鸦的食物主要以昆虫为主,占总食物量的76.7%。     

川西亚高山针叶林林窗边界木特征的研究

为探讨川西亚高山针叶林边界木树冠对林窗干扰的响应,对王朗自然保护区的这一植被类型进行了调查,分析了该类型森林中边界木的数量、树高、胸径和偏冠率的分布。结果表明：一些林窗的个别边界木个体较小,但大多数边界木个体与群落乔木层中主要树木的个体大小相一致,一个林窗中边界木的平均高度可以用来表示林窗的高度;约1／5的边界木未出现偏冠现象,绝大多数边界木的偏冠率在0．5～0．7之间(占61．72％),不同树种间的偏冠有显著差异;单个林窗的边界木最少为5株,最多为17株,平均每个林窗拥有9．51株边界木。     

红原鸡基因组序列中两段染色体未知序列的连锁定位

利用来杭鸡的蛋壳强系和弱系的F2代进行蛋壳强度相关QTL分析时，绘制了相应的连锁图谱。经过连锁分析，发现微卫星标记ABR362和ABR424分别与染色体已知的标记相连锁，分别位于1号和9号染色体。而在已经公布的红原鸡基因组序列中，这2个标记的PCR产物序列染色体尚未定位。通过连锁关系分析，这2段序列也分别定位于红原鸡1号和9号染色体上。     

家鸡(Gallus domesticus)和原鸡(Gallus gallus)的染色体及G-带带型比较研究

 本文报道了家鸡(Gallus domesticus)和中国原鸡(Gallus gallus spadiceus)的染色体组型和G-带带型.其结果是,二者的染色体数目2n=78,性染色体均为ZZ(雄性)和ZW(雌性)型;测量和计算了两种动物全部染色体(包括微小染色体)的相对长度、双臂染色体的臂比和着丝粒指数,二者各对染色体形态和相对长度基本相似,据此绘制了两种动物染色体相对长度、着丝粒指数比较模式图.对家鸡和原鸡1-19号常染色体和性染色体Z进行了G-显带,并比较和分析了二者染色体G-带带型特征,发现家鸡1号、2号染色体着丝粒区均浅染,而原鸡1号染色体长臂区域为浅染,短臂区域及2号染色体整个着丝粒区域均为深染.3-19号及性染色体Z的G-带无明显差异,据此绘制了家鸡、原鸡1-19号染色体G-带比较模式图.根据家鸡和原鸡的染色体数目、形态相似,1-19号染色体G-带同源这一事实,讨论了家鸡和原鸡的核型进化关系,进而为家鸡起源于原鸡的说法提供了细胞遗传学证据.     

原鸡不同组合F_1代肉质性状及营养成分研究

以原鸡滇南亚种(♂)与原鸡(♀)、临沧茶花鸡(♀)、绿耳乌骨鸡(♀)、楚雄麻鸡(♀)不同组合F1代为研究素材,分析比较了其常规肉质性状和基本营养成分。结果表明:原鸡杂交F1代胸、腿肌pH值显著低于原鸡纯种F1代(P<0.05),宰后24h均呈下降趋势,纯种F1代下降最为明显;胸、腿肌系水力、滴水损失率、蒸煮损失率、肌纤维直径(密度)等指标在各组间差异显著(P<0.05)。就营养成分而言,胸、腿肌水分含量及胸肌粗蛋白含量在各组间差异均不显著(P>0.05),腿肌粗蛋白含量在各组间差异显著(P<0.05);胸肌及腿肌的粗脂肪、粗灰分含量也均有显著差异(P<0.05)。总体而言,原鸡(♂)与临沧茶花鸡(♀)肉质特性杂种优势较大,与楚雄麻鸡(♀)杂种优势较小。通过了解原鸡与家鸡杂交后代肉质特性,将对野生原鸡的保种、开发利用和家鸡的杂交改良、选育实践具有实际意义。