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Beak (0):
Recent article
Beak
Abstract
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Abstract
We review the etiology, clinical features, pathology, epidemiology, and diagnosis of these DNA viruses....
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PMID: 20424393
PDF is available here.
PDF is available here.
Avian Diseases (54)2 2010
Abstract
A 12-year-old male pigeon (Columba livia) was reported to have a small lesion on the lower beak, which was diagnosed as malignant melanoma. After surgery to remove it, the general condition of the bird worsened and the bird died. Post mortem examination revealed gross, black-colored lesions in the l...
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PMID: 20608548
PDF is available here.
PDF is available here.
Abstract
We addressed these inconsistencies by considering a seldom-studied dimension of hummingbird-flower relationships, the shape of bills and flowers, through experiments on the Purple-throated Carib, Eulampis jugularis, and its major food plant, Heliconia, in the eastern Caribbean. Bills of male E. jugu...
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PMID: 19537537
PDF is available here.
PDF is available here.
Abstract
Abstract
Abstract
Feather destructive behavior is an ever-increasing problem in captive birds of prey and any associated self-mutilation can be challenging to manage. This clinical report describes a noninvasive, nonpainful, temporary beak modification technique used to prevent self-mutilation in 3 Harris' hawks (Par...
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PMID: 19530407
PDF is available here.
PDF is available here.
Abstract
We examined patterns of selection in this population by relating individual beak sizes to interannual recaptures during a prolonged drought. Supporting the theory, disruptive selection was strong between the two beak size modes. We also found some evidence of selection against individuals with the l...
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PMID: 18986971
PDF is available here.
PDF is available here.
Abstract
We further explore the morphology and molecular development of the beak skeleton and of the cranial musculature in all morphs, both in adults and juveniles (nestlings). We find a close correlation in growth between the two tissues, even though juvenile birds (nestlings) of all morphs are fed a soft...
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PMID: 19878285
PDF is available here.
PDF is available here.
Hormones and Behavior (55)1 2009
Abstract
We experimentally manipulated the yolk androgen concentrations of European Starling (Sturnus vulgaris) eggs. Subsequently we followed 49 unrelated males from hatching until year of first reproduction. We investigated the expression of multiple sexually selected male characters (song, beak color and...
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PMID: 18976657
PDF is available here.
PDF is available here.
Abstract
We assess the consequences of a niche expansion by Mexican jays (Aphelocoma ultramarina) along an elevation gradient. We predicted that jays at high elevation would have straighter bills adapted to feeding on pine cones, whereas jays at low elevation would have hooked bills adapted to feeding on aco...
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PMID: 18544512
PDF is available here.
PDF is available here.
Abstract
We first document strong and habitat-specific natural selection on bill traits linked to bite force and find adaptive modifications of bite force and bill morphology and associated divergence in courtship song between the two habitats. Second, we investigate the developmental basis of this divergenc...
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PMID: 18507745
PDF is available here.
PDF is available here.
Poultry Science (87)8 2008
Abstract
This research examined the effects of infrared beak treatment on layer chicks. Seventy-two layer chicks were assigned to hot-blade trimming (HB), infrared treatment (IR), or a control treatment. Day-old chicks were pair-housed by treatment. Beak photographs, behavior, and production indices were obt...
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PMID: 18648038
PDF is available here.
PDF is available here.
Abstract
We investigate whether the input to this "claw area" arises from dorsal thalamic neurons that, in turn, receive their somatosensory input from the gracile nucleus. After injections of biotinylated dextran amine into the gracile nucleus and cholera toxin B chain into the claw area, terminations from...
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PMID: 18461603
PDF is available here.
PDF is available here.
Developmental Biology (318)2 2008
Abstract
We locally perturb FGF signalling in the avian facial prominences with FGFR antagonists, foil barriers and FGF2 protein. We tested 4 positions with antagonist-soaked beads but only one of these induced a facial defect. Embryos treated in the lateral frontonasal mass, adjacent to the nasal slit devel...
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PMID: 18455717
PDF is available here.
PDF is available here.
Molecular Ecology (17)11 2008
Abstract
We investigate these issues using winter wrens (Troglodytes troglodytes), an unusual example of a passerine with a Holarctic distribution. Geographical variation has led to speculation that the western North American form Troglodytes troglodytes pacificus might be a distinct biological species compa...
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PMID: 18444983
PDF is available here.
PDF is available here.
Abstract
We have analyzed the subtle physical mechanism responsible for drop transport and demonstrated experimentally that the beak geometry and the dynamics of tweezering may be tuned to optimize transport efficiency. We also highlight the critical dependence of the capillary ratchet on the beak's wetting...
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PMID: 18487193
PDF is available here.
PDF is available here.
Abstract
Journal of Experimental Biology (211)Pt 10 2008
Abstract
In finches husking time is non-linearly related to the ratio of seed hardness to maximal bite force. Fringillids produce larger bite force and husk relatively hard seeds faster than estrildids of similar size. This is at least partly explained by their relatively larger jaw muscle mass and a differe...
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PMID: 18456894
PDF is available here.
PDF is available here.
Current Biology (18)8 2008
Abstract
We report for the first time results of tests with European robins, Erithacus rubecula, in total darkness and, as a control, under 565 nm green light. Under green light, the robins oriented in their normal migratory direction, with southerly headings in autumn and northerly headings in spring. By co...
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PMID: 18424144
PDF is available here.
PDF is available here.
Abstract
Abstract
We show that the hydrated beak exhibits a large stiffness gradient, spanning two orders of magnitude from the tip to the base. This gradient is correlated with a chemical gradient involving mixtures of chitin, water, and His-rich proteins that contain 3,4-dihydroxyphenyl-L-alanine (dopa) and undergo...
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PMID: 18369144
PDF is available here.
PDF is available here.
Abstract
We examined mating patterns in a population of Darwin's medium ground finches (Geospiza fortis) on Daphne Major Island to improve our understanding of how a barrier to the exchange of genes between populations arises in evolution. Body sizes of mates were weakly correlated. In one year, the smallest...
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PMID: 18211884
PDF is available here.
PDF is available here.
Abstract
We investigate the possibility of this active behaviour being associated with foraging, by studying concurrently diving and beak movement patterns in gravid females equipped with IMASEN (Inter-MAndibular Angle SENsor). 2. Four turtles provided data for periods varying from 7.3 to 56.1 h while exhibi...
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PMID: 18217943
PDF is available here.
PDF is available here.
Abstract
We used the blackbird (Turdus merula) and Isospora (an intestinal parasite) to assess whether this trade-off does indeed exist. Blackbirds were supplemented with carotenoids while simultaneously being exposed to parasites. Supplemented males circulated more carotenoids in the blood and developed mor...
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PMID: 18055388
PDF is available here.
PDF is available here.
Abstract
I constructed mechanistic models that predict filter-feeding performance for seven species of ducks directly from bill morphology and kinetics and compared these predictions to those of earlier studies that tested the bill morphology hypothesis. The models predicted that species should share a prefe...
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PMID: 18409438
PDF is available here.
PDF is available here.
Abstract
We show the improved inferential resolution of geometric morphometric methods, as applied to three hierarchical levels: (i) among seven species on Santa Cruz Island, (ii) among different sites on Santa Cruz for a single species (Geospiza fortis), and (iii) between large and small beak size morphs of...
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PMID: 18021202
PDF is available here.
PDF is available here.
Abstract
A.N. Severtsov, when introduced the concepts of ecto- and entosomatic organs, illustrated them by three examples of adaptations, namely by the blindness of some subterranean vertebrates, by the "suckers" on the geckos' fingers and toes, and by the flattened body shape of skates and rays. Morphology...
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PMID: 18669305
PDF is available here.
PDF is available here.
Molecular Ecology (17)1 2008
Abstract
We examine the influence of anthropogenic habitat changes on traits typically associated with natural and sexual selection in the little greenbul (Andropadus virens), an African rainforest bird species. Using satellite remote-sensing and field survey data, we classified habitats into nonhuman-altere...
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PMID: 17868295
PDF is available here.
PDF is available here.
Avian Pathology (36)6 2007
Abstract
This report describes a keratoacanthoma causing abnormal maxillary beak growth in a 6-year-old male budgerigar (Melopsittacus undulates). Although the bird was still capable of eating, it had recently been demonstrating signs of respiratory distress and euthanasia was recommended. On histological ex...
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PMID: 17994330
PDF is available here.
PDF is available here.
Congenital Anomalies (47)4 2007
Abstract
We explored the ontogeny of this organizing center by mapping the expression domains of both genes and their receptors and downstream targets. We tested the extent to which Shh and Fgf8 regulate each other's expression in this frontonasal organizer by either blocking or ectopically activating these...
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PMID: 17988255
PDF is available here.
PDF is available here.
Journal of Experimental Biology (210)Pt 21 2007
Abstract
We report for the first time the use and occurrence of distal rhynchokinesis in wild long-billed shorebirds feeding on small prey items suspended in water. We tested whether prey size in captive dunlins Calidris alpina influences the occurrence of distal rhynchokinesis during feeding and also whethe...
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PMID: 17951416
PDF is available here.
PDF is available here.
Journal of Anatomy (211)4 2007
Abstract
We found that aspects of the foraging patterns of Apteryx mantelli are like those of scolopacid shorebirds, suggesting that Apteryx may be using a similar prey-detection mechanism. We examined specimens of all five Apteryx species and conducted a morphological and histological examination of the bil...
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PMID: 17711422
PDF is available here.
PDF is available here.
Journal of Experimental Biology (210)Pt 20 2007
Abstract
We exposed male zebra finches (Taeniopygia guttata) to environmental stress by exposing them to two temperature regimes (6 and 26 degrees C) over a 4 week period. Simultaneously, half of the males in each temperature group were supplemented with carotenoids, whereas the other half were not. The expr...
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PMID: 17921158
PDF is available here.
PDF is available here.
Abstract
The surprisingly high prevalence of BFDV in wild eastern rosellas and sulphur-crested cockatoos has serious implications for the conservation of native parrots and the export of wild-trapped parrots and cockatoos from New Zealand. Serological studies for BFDV in wild exotic parrots, and molecular st...
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PMID: 17928900
PDF is available here.
PDF is available here.
Abstract
Flamingos are filter feeders that only rarely ingest larger food items. Their bill anatomy is adapted to the suction, filtration, and ejection of a fluid medium. This case report documents a rare case of bill impaction in a group of Caribbean flamingos (Phoenicopterus ruber) that were kept in a mixe...
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PMID: 17939357
PDF is available here.
PDF is available here.
Abstract
We conducted mate choice experiments to determine whether differences in calls or bill morphology might influence assortative mating between call types of red crossbills (Loxia curvirostra complex) that have diverged in bill structure to specialize on different species of conifers. Females preferred...
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PMID: 17714309
PDF is available here.
PDF is available here.
Abstract
Abstract
We extend our previous studies of geographically structured coevolution by considering a crossbill-conifer interaction that has persisted for a much longer time period and involves a conifer with more variable annual seed production. We examined geographic variation in the cone and seed traits of tw...
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PMID: 17767586
PDF is available here.
PDF is available here.
Poultry Science (86)9 2007
Abstract
These results suggest that acute pain is associated with both trimming methods, but that SEAR may be a preferable method, causing less check in weight gain and fewer bill morphological changes while still being effective in minimizing feather pecking damage....
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PMID: 17704368
PDF is available here.
PDF is available here.
Naturwissenschaften (94)8 2007
Abstract
We show that iron-based magnetoreception needs the presence of both of these iron minerals, their specific dimensions, shapes, and arrangements in three different subcellular compartments. We suggest that an inherent magnetic enhancement process via an iron-crusted vesicle and the attached chains of...
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PMID: 17361399
PDF is available here.
PDF is available here.
Abstract
We recently described a population of the medium ground finch, Geospiza fortis, that features large and small beak morphs with relatively few intermediates. As in other Darwin's finches of the Galápagos Islands, these morphs presumably diverged in response to variation in local food availability an...
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PMID: 17504742
PDF is available here.
PDF is available here.
Poultry Science (86)7 2007
Abstract
Beak trimming is a routine practice used in laying hens to prevent feather pecking and cannibalism. The effect of beak trimming on bird well-being depends on multiple factors, including the amount of beak that is trimmed and the quality of the procedure. The aim of this work was to determine if a re...
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PMID: 17575176
PDF is available here.
PDF is available here.
Poultry Science (86)6 2007
Abstract
The practice of beak trimming in the poultry industry occurs to prevent excessive body pecking, cannibalism, and to avoid feed wastage. To assess the welfare implications of the procedure, an emphasis of this paper has been placed on the anatomical structures that comprise the beak and mouth parts a...
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PMID: 17495105
PDF is available here.
PDF is available here.
Abstract
The purpose of this study is to delineate with high frequency ultrasound imaging the normal growth and development of the chick embryo throughout its incubation period. White Leghorn chick embryos were imaged through an opening in the egg air cell from incubation day 0-19 (Hamburger & Hamilton stage...
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PMID: 17383805
PDF is available here.
PDF is available here.
Abstract
We carried out magnetic and nonmagnetic experiments on fresh, upper-beak skin tissue samples isolated from six pairs of homing pigeons to test whether the tissue contains magnetite particles. Results of (1) room-temperature isothermal remanent magnetization (IRM) acquisition and alternating field (A...
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PMID: 16900396
PDF is available here.
PDF is available here.
Abstract
We describe the parallel speciation of finches on two small islands in the Tristan da Cunha archipelago in the South Atlantic Ocean. Nesospiza buntings are a classic example of a simple adaptive radiation, with two species on each island: an abundant small-billed dietary generalist and a scarce larg...
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PMID: 17347442
PDF is available here.
PDF is available here.
Abstract
We report that a latitudinal cline in intertidal food distribution is associated with the nonbreeding distribution of the Western Sandpiper (Calidris mauri). This novel result is the first to demonstrate a clear relationship between patterns of differential nonbreeding distribution and food availabi...
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PMID: 17503605
PDF is available here.
PDF is available here.
Abstract
Feather pecking and cannibalism are still major problems in alternative systems for laying hens. Literature and practical experience indicate that unfavourable rearing conditions might be important risk factors for the occurrence of these behavioural disturbances during the laying period. Typical re...
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PMID: 17419540
PDF is available here.
PDF is available here.
Veterinary Record (160)5 2007
Abstract
Detailed behavioural observations were made of broiler breeder chicks after their beaks had been trimmed by an automated infrared treatment at one day of age or by the traditional hot-blade method at one day or seven days, or after they had been sham-trimmed or left untreated. Observations took plac...
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PMID: 17277295
PDF is available here.
PDF is available here.
Abstract
A flurry of technological advances in molecular, cellular and developmental biology during the past decade has provided a clearer understanding of mechanisms underlying phenotypic diversification. Building upon such momentum, a recent paper tackles one of the foremost topics in evolution, that is th...
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PMID: 17187350
PDF is available here.
PDF is available here.
Abstract
Abstract
Zoological Science (23)12 2006
Abstract
I investigated what kind of associations exist between the brightness, chroma, and hue of dark integumentary patches and the size of a secondary sexual trait, the bib, in male house sparrows. I found that males with a larger bib also had a darker bib and bill, and a more saturated bib, bill, epaulet...
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PMID: 17261920
PDF is available here.
PDF is available here.
Journal of Experimental Biology (209)Pt 22 2006
Abstract
We tested this hypothesis in the zebra finch, a passerine species with a carotenoid-based signal: the colour of the bill. We simultaneously manipulated the availability of carotenoids and of a non-pigmentary antioxidant (melatonin) in the drinking water. If the antioxidant properties of melatonin pr...
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PMID: 17079711
PDF is available here.
PDF is available here.
Abstract
We tested two key predictions from this model: (1) that genetic variance exists in beak color which is a sexually selected trait, but also in condition and immune function, and (2) that positive genetic correlations exist between condition and beak color, and between beak color, condition, and immun...
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PMID: 17236429
PDF is available here.
PDF is available here.
Abstract
Journal of Experimental Biology (209)Pt 17 2006
Abstract
We measured the seed husking time and the maximal bite force of two taxa of seed cracking birds. Husking time is related to maximal bite force in a highly non-linear way and differs between estrildids and fringillids. Fringillids with the same bite force as estrildids take less time to crack seeds,...
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PMID: 16916969
PDF is available here.
PDF is available here.
Abstract
I investigate how morphological adaptation to feeding ecology influences a mating signal. In birds, changes in feeding ecology can cause rapid divergence in bill morphology. Because bills are also important for song production, feeding ecology may influence song divergence. During song, birds can ra...
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PMID: 17089977
PDF is available here.
PDF is available here.
Abstract
We hypothesize that human activities can smooth adaptive landscapes, increase hybrid fitness and hamper evolutionary diversification. We investigated this possibility by analysing beak size data for 1755 Geospiza fortis measured between 1964 and 2005 on the island of Santa Cruz, Galápagos. Some pop...
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PMID: 16822748
PDF is available here.
PDF is available here.