Specific Serological Relationships Among Partially Purified DNA Polymerases of Avian Leukosis-Sarcoma Viruses, Reticuloendotheliosis Viruses, and Avian Cells

Specific serological relationships were found among the partially purified DNA polymerases of the two groups of avian viruses whose virions contain RNA and a DNA polymerase-the avian leukosis-sarcoma viruses and the reticuloendotheliosis viruses-and three avian species which are natural hosts for these viruses: chickens, turkeys, and Pekin ducks. No relationships were found to DNA polymerases of HeLa cells or Escherichia coli. These results are consistent with the hypothesis that RNA viruses with a DNA polymerase originated from normal cellular components.     

Avian Viral Pathogens in Swallows,Zimbabwe

We sampled 417 swallows in a wetland ecosystem of Zimbabwe in February 2010 and October 2011. RT-PCR tests revealed circulation of avian paramyxovirus type I, avian influenza and West Nile disease viruses in these populations. We discuss the relevance of these findings in relation to what is known on the epidemiology of these viruses in these hosts and in relation to the host ecology. We conclude with recommendations to focus more research on Passeriformes in disease ecology and in particular on the hirundinidae family.     

Avian somatotrophs: differentiation, morphology, distribution, and regulation

Growth hormone (GH) is primarily synthesized, stored, and released by pituitary somatotrophs. These cells comprise a highly labile population that continuously undergoes proliferation, differentiation, and morphogenesis in response to changing physiological stimuli. They are also functionally and morphologically heterogeneous with distinct spatial and temporal distribution within the pituitary gland. The characteristics of these cells are discussed in this brief review.     

Avian Olfaction

The literature and status of knowledge concerning olfactionin birds is reviewed, and the general anatomical plan of theavian olfactory chamber is discussed. Birds that show olfactoryability through the possession and utilization of well-developedolfactory equipment, or are suspect of olfactory perceptionbecause of behavioral patterns or olfactory equipment are discussed.These are: (1) the kiwi (Apteryx) of New Zealand, (2) procellariiformbirds, such as albatrosses, shearwaters, and petrels, (3) thecathartine vultures, particularly the turkey vulture (Cathartesaura), (4) the oilbird (Steatornis caripensis) of the islandof Trinidad, and northern South America, and (5) the honey guidesof the family Indicatoridae. Some new data suggesting a well-developedsense of smell in the honey guides (Indicatoridae) are alsopresented.     

Avian influenza virus, a very sticky situation

The appearance of the highly pathogenic avian influenza virus H5N1 highlighted the potential impact of influenza virus on humanity. The emergence of this high profile virus stimulated much research towards a better understanding of the key determinants for successful human-to-human transmission and as such has provided new directions for therapeutic intervention strategies. For example, a phylogenetic-based grouping of influenza virus sialidases into either Group 1 or 2 has been proposed. This has provided new opportunity for the development of Group 1-specific anti-influenza drugs. Furthermore, a number of next generation sialidase inhibitors as anti-influenza drugs have also been developed.     

Avian responses to an emergent,wetland weed

African boxthorn (Lycium ferocissimum Solanaceae) is a Weed of National Significance in Australia. It is particularly problematic in Victoria and is thought to not only threaten native wildlife but also provide important habitat, particularly to birds, when there is no native alternative. In a wetland ecosystem such as a saltmarsh, boxthorn has the potential to increase structural complexity because it can stand as an emergent above surrounding vegetation. We compared bird assemblages and behaviour in saltmarsh vegetation with and without boxthorn in a coastal wetland in south‐east Australia. Species assemblage, but not richness, changed with the presence of boxthorn. The presence of singing honeyeaters (Lichenostomus virescens) and white‐fronted chats (Epthianura albifrons), the two most common native bird species (based on numerical and spatial dominance), appeared to drive these differences; singing honeyeaters preferred boxthorn while white‐fronted chats avoided it. The presence of boxthorn increased the seasonal availability of fruit and flowers, which was reflected by a high frequency of foraging for fruit and nectar where boxthorn was present. In saltmarshes without boxthorn, there was a higher frequency of foraging for insects. Some, but not all, species responded to increased structural complexity and fruit/floral resources provided by boxthorn. Consequently, management by reducing boxthorn is likely to alter bird communities and the usage of sites by some native species, thus management success should consider fine‐scale biodiversity objectives, such as managing for particular types or species of birds.     

Avian spurs

Spur size and number in the various species of Galliformes are considered in relation to body size and social system. Spur length is absolutely and relatively greater among large tropical species. Multiple-spurred species are intermediate in size between spurless and single-spurred species, but have longer legs. Possession of spurs is common, and presumably originated among monogamous species, but is still commoner among polygamous ones. Different spur shapes possibly reflect wounding versus stunning strategies of fighting. Wing spurs in other birds are briefly compared.     

Avian long bones, flight and bipedalism.

Morphological, geometrical, chemical and mechanical characteristics of avian long bones are reviewed. Important differences exist between long bones of birds and mammals. Differences are also present in appendicular bones of birds, either between wing bones and leg bones or proximal (stylopodial) long bones and distal (zeugopodial) long bones. Special emphasis is put on pneumatization, in terms of both phylogenetic origin and geometrical and mechanical characteristics linked to it. Cortical thickness, bending strength and flexural Young's modulus were significantly lower in pneumatized bones than in marrow-filled bones. Possible adaptive reasons for the differences shown are discussed.     

Avian SDMs: current state,challenges, and opportunities

Quantifying species distributions using species distribution models (SDMs) has emerged as a central method in modern biogeography. These empirical models link species occurrence data with spatial environmental information. Since their emergence in the 1990s, thousands of scientific papers have used SDMs to study organisms across the entire tree of life, with birds commanding considerable attention. Here, we review the current state of avian SDMs and point to challenges and future opportunities for specific applications, ranging from conservation biology, invasive species and predicting seabird distributions, to more general topics such as modeling avian diversity, niche evolution and seasonal distributions at a biogeographic scale. While SDMs have been criticized for being phenomenological in nature, and for their inability to explicitly account for a variety of processes affecting populations, we conclude that they remain a powerful tool to learn about past, current, and future species distributions – at least when their limitations and assumptions are recognized and addressed. We close our review by providing an outlook on prospects and synergies with other disciplines in which avian SDMs can play an important role.     

Avian hybridization, mixed pairing and female choice

A review of behavioural studies of hybridization and mixed pairing in birds led to the following conclusions. (1) Hybridization is more common where one of two hybridizing species is rare. (2) There is no tendency in mixed pairs or in interspecific copulations for females to belong to a rarer species than males, as would be predicted by theory based on female choice. (3) There is no evidence that females prefer males of a larger species when hybridizing, in sympatric or in parapatric species. I propose three hypotheses to account for these findings. (1) Scarcity of conspecifics facilitates hybridization in general, no matter which sex is the rare one. (2) Mistakes in mate recognition cause hybridization, especially when females choose wrongly. (3) Supernormal stimuli may sometimes cause hybridization. It is not possible to judge which of these hypotheses is the best supported, and hybridization is likely to have multiple causes.