The influence of geographic and morphometric factors on the distribution of water bird species in small high altitude tropical man made reservoirs,Central Rift Valley,Kenya

Variability in waterfowl characteristics among eight high altitude (2040–2640 m) small shallow (0.065–0.249 km²; 0.9–3.1 m) reservoirs in the escarpment zone along the central rift valley in Kenya between Naivasha and Nakuru towns were studied between 1998 and 2000. The aim of the study was to establish whether the geographic status of small reservoirs in terms of altitude and surface gradient can affect the characteristics of their birdlife in terms of bird counts and species numbers. The study also aimed at establishing whether reservoir bird counts and species number can be predicted by reservoir morphometric factors especially water depth, surface area, length of shoreline and area‐shoreline ratio. The other aim was to determine the influence of local environment especially distance from the nearest natural lakes, and house density on the birdlife. The findings showed that geographic location of the reservoirs in terms of altitude and landscape had a strong influence on birdlife whereby reservoirs in higher altitude and flat plateau landscape were found to support higher bird species and counts. Larger and deeper reservoirs were richer in water bird species but small and shallow reservoirs were superior in terms of both bird species and counts. Reservoirs with more coarse, irregular and highly erratic shorelines had higher species number than those with smooth and well‐rounded shorelines. The reservoir birdlife was found to be influenced by the number of farm houses near the waterbodies and also the distance from the nearby rift valley lakes. The results showed that both geographic and morphometric considerations are necessary in the establishment of new reservoirs especially for utilization in birdlife conservation and ecotourism.     

Structural coloration in a fossil feather

Investigation of feathers from the famous Middle Eocene Messel Oil Shale near Darmstadt, Germany shows that they are preserved as arrays of fossilized melanosomes, the surrounding beta-keratin having degraded. The majority of feathers are preserved as aligned rod-shaped eumelanosomes. In some, however, the barbules of the open pennaceous, distal portion of the feather vane are preserved as a continuous external layer of closely packed melanosomes enclosing loosely aligned melanosomes. This arrangement is similar to the single thin-film nanostructure that generates an iridescent, structurally coloured sheen on the surface of black feathers in many lineages of living birds. This is, to our knowledge, the first evidence of preservation of a colour-producing nanostructure in a fossil feather and confirms the potential for determining colour differences in ancient birds and other dinosaurs.     

Uneven Rates of Landscape Change as a Source of Bias in Roadside Wildlife Surveys

ABSTRACT Roadside survey data have been used frequently to assess species occurrence and population trends and to establish conservation priorities. However, most studies using such data assume that samples are representative of either the amount of habitat or its rate of change at larger spatial scales. We tested both of these assumptions for the Breeding Bird Survey (BBS) from 1974 to 2001 in New Brunswick, Canada. Our study focused on mature forest—a cover type that we predicted would be characterized by rapid change due to human activities and that is of high ecological importance. We also sought to determine whether land cover changes adjacent to BBS routes were related to bird population trends detected in BBS data. Within all 3 time periods examined (1970s, 1980s, and 1990s), the amount of mature forest adjacent to BBS routes was significantly lower than in surrounding 1° blocks of latitude and longitude. This could be problematic for studies that use roadside data to compare the relative abundance of species. On average, mature forest declined at a rate of-1.5% per year over the 28-year study period. We detected no significant difference in the rate of change between degree blocks and BBS routes over this time span. However, in the 1970s and 1980s, mature forest declined more rapidly in degree blocks (-2.7%/yr) than adjacent to BBS routes (-0.5/yr). We also found that the BBS trend for a mature forest-associated species, blackburnian warbler (Dendroica fusca), was correlated with the trend in mature forest along BBS routes. This, combined with slower rates of mature forest change along routes in the 1970s and 1980s, suggests that BBS data may have underestimated population declines during this period. It is important that research be conducted to test for potential biases in roadside surveys caused by uneven rates of landscape change, particularly in regions characterized by rapid habitat alteration.     

Estimating Wind Turbine-Caused Bird Mortality

ABSTRACT Mortality estimates are needed of birds and bats killed by wind turbines because wind power generation is rapidly expanding worldwide. A mortality estimate is based on the number of fatalities assumed caused by wind turbines and found during periodic searches, plus the estimated number not found. The 2 most commonly used estimators adjust mortality estimates by rates of searcher detection and scavenger removal of carcasses. However, searcher detection trials can be biased by the species used in the trial, the number volitionally placed for a given fatality search, and the disposition of the carcass on the ground. Scavenger removal trials can be biased by the metric representing removal rate, the number of carcasses placed at once, the duration of the trial, species used, whether carcasses were frozen, whether carcasses included injuries consistent with wind turbine collisions, season, distance from the wind turbines, and general location. I summarized searcher detection rates among reported trials, and I developed models to predict the proportion of carcasses remaining since the last fatality search. The summaries I present can be used to adjust previous and future estimates of mortality to improve comparability. I also identify research directions to better understand these and other adjustments needed to compare mortality estimates among wind farms.     

Climate and demography of the planktivorous Cassin's auklet Ptychoramphus aleuticus off northern California: implications for population change

1. We performed demographic analyses on Cassin's auklet Ptychoramphus aleuticus, a zooplanktivorous seabird inhabiting the variable California Current System, to understand how temporal environmental variability influences population dynamics. 2. We used capture-recapture data from 1986 to 2002 to rank models of interannual variation in survival, breeding propensity, breeding success, and recruitment. 3. All demographic parameters exhibited temporal variability. Interannual variation in survival was best modelled as a nonlinear function of the winter Southern Oscillation Index (SOI). Breeding propensity was best modelled as a threshold function of local sea surface temperature. Breeding success and recruitment were best modelled with year-dependent annual variation. 4. Changes in the SOI force El Ni?o/La Ni?a events, which in turn alter prey availability to seabirds in this system. Demographic responses varied during El Ni?os/La Ni?as. Survival diminished substantially during the 1997-98 El Ni?o event, while breeding propensity was affected during both the 1992 and 1998 El Ni?os. Breeding success was reduced during the 1992, 1993, and 1998 El Ni?os, but was unusually high in 2002. Recruitment was higher at the beginning and end of this time-series. 5. While demographic responses varied interannually, parameter values covaried in a positive fashion, a situation conducive to rapid population change. During the 11 years study period, the Farallon auklet breeding population declined at 6.05 +/- 0.80% (SE) per year, a cumulative decline of 49.7%. This study demonstrates how climate variability has influenced key demographic processes for this diminished marine bird population.     

吉林珲春2002～2005年鸟类环志监测报告

2002～2005年在吉林省珲春市马川子乡依力南沟开展了鸟类环志研究工作。这里为长白山低山丘陵区,是候鸟经长白山脉、乌苏里江迁徙途中重要的停歇地和食物补给站。4年共环志鸟类126种63386只,其中春季103种9761只,秋季113种53625只,隶属13目37科。春季以黄喉鸦（Emberiza elegans）为迁徙鸟类的优势种,环志2467只,占春季环志数量的25．3％;秋季以黄喉鸦、红胁蓝尾鸲（Tarsiger cyanurus）、黄眉柳莺（Phylloscopus inornatus）、大山雀（Parus major）、白眉鸦（E.tristrami）、极北柳莺（P.borealis）等6种为迁徙鸟类的优势种,累计33586只,占秋季环志数量的62．6％;通过环志研究发现,被认为是留鸟的大山雀、银喉长尾山雀（Aeghhalos caudatus）、沼泽山雀（P.palustris）、长尾雀（Uragus sibiricus）具有定期的迁徙行为。     

广州市越秀公园鸟类多样性与保护对策

对广州市越秀公园鸟类的多样性进行了调查,共记录鸟类43种,隶属8目20科。其中留鸟27种,夏候鸟2种,冬候鸟8种,其它繁殖鸟6种。对夏冬季及不同生境的鸟类群落特征进行比较分析,得到夏季鸟类的数量、密度、优势度都比冬季高,而多样性指数和均匀性指数却比冬季低;南秀湖畔大草坪、金印游乐场、竹林、南秀树林、南秀湖和环市路旁6种生境中鸟类的种类、数量和多样性差异较大,以金印游乐场鸟类的多样性最高。根据公园内不同环境鸟类多样性状况提出了保护对策。     

武汉桂子山地区冬季鸟类群落结构及多样性研究

2005年11月～2006年3月,对武汉桂子山地区冬季鸟类群落进行了调查,共记录鸟类44种,隶属10目22科。有国家Ⅱ级保护鸟类2种,湖北省重点保护鸟类16种;留鸟32种,冬候鸟11种,旅鸟1种,留鸟构成了冬季鸟类的主体;该地区冬季鸟类密度为4．30只／hm^2,物种多样性指数为2．6477,均匀性指数为0．6997。居民点、乔灌林、绿地和水域生境中,乔灌林鸟类多样性最高,数量最多。     

四川嘛咪泽自然保护区不同生境类型鸟类多样性调查

2006年4~5月采用样点法对四川嘛咪泽自然保护区的鸟类组成和种群数量进行了调查,共记录到鸟类7目23科105种,数量1948只,其中国家重点保护鸟类6种,我国特有鸟类7种。鸟类区系以东洋界成分为主。对不同生境鸟类多样性的分析结果表明:1)人工林和灌丛草地生境间的鸟类群落相似性指数最高,灌丛草地和原始林之间鸟类群落相似性最低;2)次生林鸟类多样性指数最高,灌丛草地最低;3)原始林内国家级保护鸟类最多,特有种仅次于次生林;4)林中鸟类垂直分布中间层密度最大。