The biogeography of avian extinctions on oceanic islands revisited

A recent paper by Karels et al ., 'The biogeography of avian extinctions on oceanic islands' ( Journal of Biogeography , 2008, 35 , 1106–1111), uses structural equation modelling to assess the causes of the number of island bird species driven extinct in the historical period. Here, we critically assess the conclusions of the paper and argue that it does not provide the new insights into the causes of extinction in island birds that its authors claim.     

鸭绿江河口湿地鸟类生境的破坏与修复

鸭绿江河口湿地国家级自然保护区共发现鸟类210种,目前只是在核心区才保留有少许的自然生境--黑嘴鸥(Larus saundersi)的巢址,生境破碎化、片段化现象严重.文章运用景观生态学、恢复生态学、保护生物学的原理和方法、兼顾保护与发展,遵循可持续发展的基本思想,进行生境修复,加强生态管理,使得鸭绿江河口湿地真正成为众多鸟类迁徙路上理想的歇脚地、加油站.     

Environmental and genetic variation in T-cell-mediated immune response of fledgling American kestrels

We investigated genetic and environmental components of variance in avian T-cell-mediated immune response (CMI) through a cross-fostering experiment conducted on wild American kestrels (Falco sparverius). CMI was evaluated in vivo by an experimental challenge with phytohaemagglutinin, a T-cell mitogen, injected intradermally in fledglings. Additionally, we assessed two measures of nutritional condition (body mass and circulating plasma proteins) which could influence the variance components of CMI. A two-way nested ANOVA indicated that CMI of fledgling kestrels was explained more by the nest where the bird was reared (33% of the explained variance) than by the nest of origin (12%). Body mass was explained equally by familial and environmental components, while plasma proteins were only related to the rearing environment. CMI of fledglings was not related to their circulating plasma proteins, but was positively correlated with their body mass. Fledgling body mass seemed to be influenced by pre-hatching or post-hatching maternal effects prior to manipulation since resemblance in body mass of sibships at the age of manipulation was high (h ²≤0.58), and body mass at this age predicted body mass at fledging. Therefore, pre-manipulation parental effects on body mass, such as investment in egg size, could have inflated the familial effects on body mass of fledglings and then on its correlated CMI. When controlling for body mass, most of the variation in CMI of fledglings was explained by the nest where the bird was reared (36.6%), while the variance explained by the nest of origin (4%) was not significant. This means that environmental influences are major determinants of offspring CMI. The low proportion of variance explained by the familial component may have been due to the high correlation of CMI to fitness. Received: 19 October 1999 / Accepted: 23 December 1999     

National-scale conservation assessments at an appropriate resolution

Abstract.  Most national-scale conservation assessments are carried out at a resolution that is different from the actual size of protected areas in the study region. Coincidence between nature reserves and both hotspots (areas of high species richness) and complementary areas (sets of sites within which all species are represented) have been reported. However, the resolution (size of grid cells) of the species' distribution data upon which many of these studies are based is often close to an order of magnitude larger than the size of the reserves. Presumably, only a proportion of the species recorded in the coarse grid cells will actually be present on reserves. We use fine (2 × 2-km square grid cells) and coarse (10 × 10-km square grid cells) resolution data of national distributions for breeding birds throughout Great Britain, and presence data for avian species on Royal Society for the Protection of Birds (RSPB) nature reserves, to investigate the proportion of species in the local area (100 km²) that are actually present on reserves. RSPB reserves contain between 50% and 70% of species from the local area. These proportions are significantly higher than for randomly selected, non-reserve areas, indicating that RSPB reserves contain higher concentrations of bird species than the wider countryside. Furthermore, on RSPB reserves these proportions of threatened and non-threatened species are equal, whereas in non-reserve areas the proportions of non-threatened species are significantly higher than threatened species. Thus, reserves hold a higher proportion of threatened species than occurs in the wider countryside.     

Reduced abundance of raptors in radioactively contaminated areas near Chernobyl

The negative ecological effects of radioactive contamination around Chernobyl have recently been suggested to be moderate and declining because of an increasing number of anecdotal observations of several species of rare animals including predators. However, these claims were not based on empirical evidence. Radionuclides show bio-accumulation with trophic level, and the abundance of birds is depressed in radioactively contaminated areas around Chernobyl. Therefore, we predicted that birds of prey should be less abundant with increasing levels of radiation. Here, we use our long-term field data from 1991 to 2007 in three different analyses based on observations of raptors using standardized point counts, censuses during capture of barn swallows Hirundo rustica that habitually give alarm calls when a raptor is present, and line transects while driving on roads. Analyses suggest that the abundance of birds of prey is reduced in contaminated areas, and that there is evidence of a recent increase in abundance of raptors in less contaminated areas, but not in the most contaminated ones. Our findings suggest that birds of prey that are top level consumers in ecosystems suffer from reduced abundance in radioactively contaminated areas.     

Slow evolution of transferrin and albumin in birds according to micro-complement fixation analysis

Summary Rabbit antisera were prepared to purified ovotransferrin from chicken (order Galliformes) and red-winged blackbird (order Passeriformes) and to purified serum albumin from chicken and rhea (order Rheiformes). Quantitative microcomplement fixation was used to compare these proteins immunologically with those of representatives of all 27 orders of birds. The average interordinal immunological distances were 123 units for transferrin and 53 units for albumin.Extensive intraordinal comparisons of transferrin among 51 species within the order Galliformes and 33 species within the order Passeriformes were also carried out. Values ranging from 0–75 immunological distance units were found within each order.Rabbit antisera to purified alligator albumin were also prepared and shown to react with representatives of all 27 orders of birds, the average immunological distance being 166 units.When the data presented here are considered in relation to the fossil record of birds, it appears that transferrin and albumin have evolved more slowly in birds than in other vertebrates. If prevailing interpretations of the fossil record are correct, transferrin has evolved 2–4 times as fast in mammals and snakes as in birds, while serum albumin has evolved about 3 times as fast in mammals, iguanids, crocodilians, and frogs as in birds. Published immunological and sequence comparisons of lysozyme and cytochromec are also consistent with a slower rate of evolution in birds than in other vertebrates. The implications of a general slowdown in the evolution of bird proteins are discussed.This research was supported in part by grants from the National Science Foundation and the National Institutes of Health to A. C. Wilson and fellowship awards to A. H. Brush and R. A. Nolan (from NIH) and A. C. Wilson (from the Guggenheim Foundation). A preliminary account of part of this work was presented at the International Congress of Systematic and Evolutionary Biology in Boulder, Colorado, on August 9, 1973.The following abbreviations are used in this work: RWBB = red-winged blackbird; OT = ovotransferrin; EW = egg white; TE = tissue extract; ND = not done; MY = million years.     

Variation in numbers and behaviour of waders during the tidal cycle: implications for the use of estuarine sediment flats

Estuarine sediment flats are essential feeding areas for waders, but their exploitation is constrained by the movements of tides. In this cyclic environment the exposure period of sediment flats decreases several fold from upper to lower flats, and the moving tidal waterline briefly creates particular conditions for waders and their prey. This study attempts to determine how the exposure period and the movement of the tide line influence the use of space and food resources by waders across the sediment flats. Wader counts and observations of feeding behaviour were carried out in all phases of the tidal cycle, in plots forming a transect from upper to lower flats, thus representing a gradient of exposure periods. Pecking, prey intake, and success rates varied little along the gradient. Some species actively followed the tide line while foraging, whereas others are evenly spread over the exposed flats. Black-tailed Godwit, Dunlin and Avocet were 'tide followers', whereas Grey Plover, Redshank and Bar-tailed Godwit were 'non-followers'. Densities of 'followers' near the tide line were up to five times higher than elsewhere. Species differed markedly in the way they used space on the flats, but in general the rate of biomass acquisition (in grams of ash-free dry weight per time exposed) was much higher in lower flats. However, this preference was insufficient to counter the much longer exposure of the upper flats, so the total amount of biomass consumed on the latter was greater. Therefore, it was in these upper flats that waders fulfilled most of their energetic needs. Consequently, upper flats are of particular importance for the conservation of wader assemblages, but because they are usually closer to shore they tend to suffer the highest pressure from disturbance and land reclamation.     

Julije Klovi?: the first colour drawing of Greater Bird of Paradise Paradisaea apoda in Europe and its model

The prayer book The Hours of the Blessed Virgin Mary, known as The Farnese Hours, was illustrated by the Croatian miniaturist, Julije Klović, between 1539 and 1546 in Rome. In this masterpiece of Renaissance miniature art, Klović drew in colour a bird of paradise. In 2001, the pictured bird was determined to be a Raggiana Bird of Paradise, Paradisaea raggiana P. L. Sclater 1873. Our later determination shows that it is actually a Greater Bird of Paradise Paradisaea apoda (Linnaeus 1758) and the first drawing of this species in colour in Europe. Klović’s model for the Greater Bird of Paradise was one of the first trade skins of birds of paradise that, from 1522, had been arriving in Europe. Revision of the early drawings of the birds of paradise species in Europe, relevant to the Klović drawing model, has also been carried out and is discussed.     

Reconsidering locomotor habits and life style of the Balearic insular giant rodent Hypnomys Bate, 1918 from the allometry of the limb long bones

The genus Hypnomys Bate, 1918 includes some endemic Neogene chronospecies from Mallorca and Menorca, evolved in insularity conditions from the Lower Pliocene to the human arrival at the archipelago. The study of the allometric proportions (functional length and sagittal diameter) of the limbs’ long bones of Hypnomys eliomyoides Agusti, 1980 (Lower Pleistocene of Menorca), Hypnomys sp. (Pleistocene of Menorca), Hypnomys onicensis (Reumer, 1994) (Upper Pliocene-Lower Pleistocene of Mallorca) and Hypnomys morpheus Bate, 1918 (Upper Pleistocene of Mallorca) only indicates small differences with the garden dormouse (Eliomys quercinus Linnaeus, 1776) and other mainland rodents and insectivores. The study about the locomotion type by means of Similarity Matrix of Bou indicates that 1) Hypnomys spp. presents the greater similarities with the arboreal, jumping and gliding species; 2) the jumping and digging life style of Hypnomys spp. are more developed (25%) than in E. quercinus; 3) the walking locomotion of Hypnomys spp. is only a 7% greater than in E. quercinus; and 4) the degree of similarity with the gliding locomotion of Hypnomys sp. is greater (17%) than in E. quercinus. Some of this data indicates that Hypnomys spp. was better adapted to the arboreal life than E. quercinus, due to the relationship between the jumping and gliding capacities with the arboreal locomotion. The greater similarity of Hypnomys spp. with the walking locomotion does not necessarily involve more terrestrial habits. Our interpretation contrasts with earlier conclusions of Hypnomys life style (Hypnomys cf. onicensis and Hypnomys morpheus) where the terrestrial locomotion was overestimated in front of the arboreal locomotion. The locomotion type of Hypnomys would be related with the presence of important forest masses on the Balearic Islands during the Neogene, a different degree of environmental stress from that of the mainland ecosystems and a probable expansion of the ecological niche occupied by these species.