CiteULike: Tag bird

Segregation of information in a complex acoustic signal: individual and dialect identity in white-crowned sparrow song

Douglas Nelson — 2007-10-29T09:15:03-00:00

Animal Behaviour, Vol. 74, No. 4. (October 2007), pp. 1073-1084.

Many bird songs are highly complex acoustic signals that broadcast a variety of information over long distances. General explanations for signal complexity assume that either different signal components are redundant, or that each component conveys a different message. Puget Sound white-crowned sparrow, Zonotrichia leucophrys pugetensis, song consists of several temporally discrete phrases or components, two of which, the note complex and trill, vary independently across vocal dialects. Previous playback experiments with males suggest that the terminal trill encodes dialect identity. Here we test whether both the note complex and trill encode individual identity, as predicted by the redundancy hypothesis, or whether the note complex alone serves this role, as predicted by the multiple messages hypothesis. Analyses of acoustic variation in note complexes and trills, and results of a neighbour-stranger song discrimination playback experiment support the multiple messages hypothesis. Note complexes were more individually distinctive among males, and males responded stronger when a neighbour's song had a stranger's note complex substituted than when the neighbour's trill was replaced with that of a stranger. The segregation of cues to individual and dialect identity into the note complex and trill phrases, respectively, supports the hypothesis that coding conflicts may be resolved by using different song components for different functions.

Temporal Hierarchical Control of Singing in Birds

Albert Yu — 2007-06-06T14:25:59-00:00

Science, Vol. 273, No. 5283. (27 September 1996), pp. 1871-1875.

10.1126/science.273.5283.1871

Automatic Recognition and Analysis of Birdsong Syllables from Continuous Recordings

Sven Anderson — 2007-07-03T02:48:29-00:00

We describe a technique for the automated analysis of continuous, unsegmented animal vocalizations. The algorithm is based on the comparison of templates with unknown signals using a dynamic time-warping (DTW) algorithm. It directly compares signal spectrograms, and identifies constituents and constituent boundaries, thus permitting the identification of a broad range of signals and signal components. When applied to the vocalizations of an indigo bunting (Passerina cyanea) and a zebra finch...

The heterozygosity theory of extra-pair mate choice in birds: a test and a cautionary note

Sarah Smith — 2005-03-01T14:30:30-00:00

Journal of Avian Biology, Vol. 36, No. 2. (February 2005), pp. 146-154.

Lack of canonical E6 and E7 open reading frames in bird papillomaviruses: Fringilla coelebs papillomavirus and Psittacus erithacus timneh papillomavirus.

M Terai — 2006-12-30T12:53:24-00:00

J Virol, Vol. 76, No. 19. (October 2002), pp. 10020-10023.

Determination and analyses of the complete sequence of Fringilla coelebs papillomavirus and Psittacus erithacus timneh papillomavirus indicate that they represent a distinct and distant lineage of papillomaviruses. The lack of canonical E6-E7 open reading frames suggests that they serve adaptive functions during papillomavirus evolution.

Ecosystem consequences of bird declines.

CH Sekercioğlu — 2006-01-19T21:01:38-00:00

Proc Natl Acad Sci U S A, Vol. 101, No. 52. (28 December 2004), pp. 18042-18047.

We present a general framework for characterizing the ecological and societal consequences of biodiversity loss and applying it to the global avifauna. To investigate the potential ecological consequences of avian declines, we developed comprehensive databases of the status and functional roles of birds and a stochastic model for forecasting change. Overall, 21% of bird species are currently extinction-prone and 6.5% are functionally extinct, contributing negligibly to ecosystem processes. We show that a quarter or more of frugivorous and omnivorous species and one-third or more of herbivorous, piscivorous, and scavenger species are extinction-prone. Furthermore, our projections indicate that by 2100, 6-14% of all bird species will be extinct, and 7-25% (28-56% on oceanic islands) will be functionally extinct. Important ecosystem processes, particularly decomposition, pollination, and seed dispersal, will likely decline as a result.

Extra-pair fertilization and effective population size in the song sparrow Melospiza melodia

D O'Connor — 2006-11-02T06:58:35-00:00

Journal of Avian Biology, Vol. 37, No. 6. (November 2006), pp. 572-578.

Fitness consequences of hybridization between house sparrows (Passer domesticus) and tree sparrows (P. montanus)

Erling Solberg — 2007-06-13T10:35:17-00:00

Journal of Ornithology, Vol. 147, No. 3. (6 July 2006), pp. 504-506.

Abstract Gene transfer may occur following hybridization between closely related species if hybrids are viable and able to breed with individuals of one or both of the parental species. House (Passer domesticus) and tree sparrows (P. montanus) occasionally hybridize and produce viable offspring. Previously, we concluded that male tree × house sparrow hybrids are most probably fertile based on the observation of a male F1 hybrid feeding the nestlings with a female house sparrow in two consecutive clutches. However, recent DNA analyses based on blood samples revealed that all nestlings (4) in the first clutch were sired by a neighbouring house sparrow male, whereas nestlings in the second clutch (2) were not blood sampled and most probably died before fledging. This indicates that extensive extra-pair fertilization confounded our previous conclusion, and indicates that social partnership and attending behaviour can be imprecise measures of paternity.

Extra-pair fertilizations in Tree Sparrows Passer montanus

Pedro Cordero — 2007-06-13T10:35:07-00:00

Ibis, Vol. 144, No. 2. (2002), pp. E67-E72.

Females of socially monogamous bird species frequently accept or solicit copulations from males other than their social mates. At the interspecific level, it has been proposed that species with few or no sexual plumage differences have lower levels of extra-pair fertilizations (EPFs) than more dichromatic species. This is because it is easier for females to assess the quality of extra-pair mates in dichromatic than monochromatic species. To test this, by using genetic profiling, we compared the occurrence of extra-pair young in nests of Tree Sparrows Passer montanus, a monochromatic species, in Switzerland and Spain, with published estimates for the House Sparrow Passer domesticus, a closely related dichromatic species. We found that 25% (10/40) of Tree Sparrow broods in Spain and 23% (8/35) in Switzerland had at least one extra-pair offspring, and that 8% (12/151) of nestlings in Spain and 10% (12/114) in Switzerland were sired by extra-pair mates. These proportions did not differ significantly between the two populations. Tree Sparrow EPF rates did not differ significantly from available data for the House Sparrow, either in the proportion of broods with EPF young (24%, 18/75 in Tree vs. 26%, 92/359 in House Sparrows) or the overall proportion of extra-pair young (9%, 24/265 in Tree vs. 11%, 142/1110 in House Sparrows). Our results suggest that a close taxonomic relationship and similarities in behaviour and ecology may be more important in determining levels of EPF in these species than sexual phenotypic differences.

Reproductive effort of colonial and solitary breeding tree sparrows Passer montanus L.

Lajos Sasvári — 2007-06-13T10:34:58-00:00

Behavioral Ecology and Sociobiology, Vol. 34, No. 2. (1 February 1994), pp. 113-123.

A total of 250 nestboxes were arranged in five plots in a suburban area of Budapest, Hungary (19°04'E, 47°41'N). In each plot, 25 were placed at 50 m intervals to simulate solitary breeding and 25 3–5 m apart to simulate colonial breeding. Length of nest building period, feeding frequency, nestling mortality, nestlings' diet, productivity and parental condition were compared for colonial and solitary breeding tree sparrows Passer montanus. Parents with long nest-building periods, including the majority of first-year females, produced fewer young than parents which built over short periods. Parents fed nestlings morefrequently and nestlings had lower mortality in second than first broods; whether or not a third brood was reared was determined by the costs invested in first and second broods. Females that laid a third clutch had reared fewer young in first and second broods and were heavier than females that reared many young in two broods. Colonial birds had higher feeding frequencies, more similar diets and suffered lower nestling mortality than solitary parents for first broods, but they fed less frequently, diets were less similar, and nestling mortality was higher in second and third broods. It is suggested that colonial breeders benefited from the social stimulation of simultaneous feeding in first broods, but the advantage of synchronicity in feeding declined in second broods and the sparser breeding spacing of solitary parents was more advantageous for feeding in second and third broods. Birds that changed nest spacing between broods had fed nestlings less frequently and had higher nestling mortality before changing than birds which retained their spacing. Parents which changed from colonies to solitary nests fed more frequently with lower nestling mortality in the next brood than parents which retained colonial nests for their second (and third) brood. Solitary parents did not show such a relationship. The rearing of three broods caused higher weight loss in colonial than solitary parents.

Escape flight in moulting Tree Sparrows (Passer montanus)

Lind — 2006-03-21T18:25:01-00:00

Functional Ecology, Vol. 15, No. 1. (2001), pp. 29-35.

Summary 1. Impaired predator evasion in birds as a cost in different life-history periods has received increasing attention in the last decade. Evasive abilities in birds have been found to be detrimentally affected by migratory fuel load, reproduction and moult. These results suggest that during these periods of their lives birds suffer from increased predation risk due to impaired evasive abilities. 2. Theoretically, moult should have a detrimental effect on flight, and empirical work on starlings has shown impaired escape ability due to moult. However, a recent theoretical investigation found a surprisingly small effect of moult on flight in birds. 3. In this study, 31 Tree Sparrows, a sedentary species with a slow moult, were used to investigate the effect of natural and manipulated moult on escape ability. No effect was found due to natural moult, however, when experimentally increasing moult gap size a strong negative effect was found. 4. With support from empirical and theoretical work, this is the first study to suggest that slow moult may not increase predation risk due to impaired evasive abilities. Compensatory physiological adaptations probably cause this result and may be very important during moult. 5. Predation risk is probably an important factor in the evolution of moult patterns and moult strategies.

Can video images imitate real stimuli in animal behaviour experiments?

Richard D'Eath — 2007-06-13T10:32:44-00:00

Biological Reviews, Vol. 73, No. 3. (1998), pp. 267-292.

ABSTRACT The use of video images in place of natural stimuli in animal behaviour experiments is reviewed. Unlike most other artificial means of stimulus presentation, video stimuli can depict complex moving objects such as other animals, preserving the temporal and spatial patterns of movement precisely as well as colour and sounds for repeated playback. Computer editing can give flexibility and control over all elements of the stimulus. A variety of limitations of video image presentation are also considered. Televisions and video monitors are designed with human vision in mind, and some non-human animals that differ in aspects of visual processing such as their colour vision, critical flicker-fusion threshold, perception of depth and visual acuity, may perceive video images differently to ourselves. The failure of video stimuli to interact with subjects can be a drawback for some studies. For video to be useful, it is important to confirm that the subject animal responds to the image in a comparable way to the real stimulus, and the criteria used to assess this are discussed. Finally, the contribution made by video studies to date in the understanding of animal visual responses is considered, and recommendations as to the future uses of video are made.

Foraging behaviour and feeding ecology of the Black-cheeked Lovebird Agapornis nigrigenis in Zambia

LS Warburton — 2005-11-05T04:24:06-00:00

Ostrich - Journal of African Ornithology, Vol. 76, No. 3-4. (October 2005), pp. 118-129.

Diet and foraging behaviour of the Rosy-faced Lovebird Agapornis roseicollis in Namibia

Ndithia — 2006-04-24T18:49:15-00:00

Ostrich - Journal of African Ornithology, Vol. 77, No. 1-2. (April 2006), pp. 45-51.

Out of Gondwanaland; the evolutionary history of cooperative breeding and social behaviour among crows, magpies, jays and allies

Jan Ekman — 2007-06-13T10:20:56-00:00

Proceedings of the Royal Society B: Biological Sciences, Vol. 273, No. 1590. (7 May 2006), pp. 1117-1125.

Cooperative breeding is comparatively rare among birds in the mainly temperate and boreal Northern Hemisphere. Here we test if the distribution of breeding systems reflects a response to latitude by means of a phylogenetic analysis using correlates with geographical range among the corvids (crows, jays, magpies and allied groups). The corvids trace their ancestry to the predominantly cooperative ‘Corvida’ branch of oscine passerines from the Australo-Papuan region on the ancient Gondwanaland supercontinent, but we could not confirm the ancestral state of the breeding system within the family, while family cohesion may be ancestral. Initial diversification among pair-breeding taxa that are basal in the corvid phylogeny, represented by genera such as Pyrrhocorax and Dendrocitta, indicates that the corvid family in its current form could have evolved from pair-breeding ancestors only after they had escaped the Australo-Papuan shield. Within the family, cooperative breeding (alloparental care/family cohesion) is strongly correlated to latitude and its predominance in species maintaining a southerly distribution indicates a secondary evolution of cooperative breeding in the lineage leading away from the basal corvids. Multiple transitions show plasticity in the breeding system, indicating a response to latitude rather than evolutionary inertia. The evolutionary background to the loss of cooperative breeding among species with a northerly distribution is complex and differs between species, indicating a response to a variety of selection forces. Family cohesion where the offspring provide alloparental care is a main route to cooperatively breeding groups among corvids. Some corvid species lost only alloparental care, while maintaining coherent family groups. Other species lost family cohesion and, as a corollary, they also lost the behaviour where retained offspring provide alloparental care.

Oviductal Function during the Annual Ovarian Cycle of a Wild Avian Species, the Tree Pie Dendrocitta vagabunda

S Chaudhuri — 2007-06-13T10:27:07-00:00

pp. 290-296.

The present investigation was carried out on oviductal activity during the annual ovarian cycle of the Indian tree pie ( Dendrocitta vagabunda ). The oviductal activity was evaluated by weight, length, histology (gross and quantitative) and peroxidase, acid phosphatase, alkaline phosphatase, sialic acid, glycogen, RNA and protein concentrations of different regions of the oviduct. All these values w ere low during the nonbreeding phase (August to January), increased during the progressive phase (February to March), became maximum during breeding (April to May) and decreased in the regression phase (June to July). The functional change of the oviduct is suggested to be due to fluctuation of ovarian steroid activity in this avian species.

Orchestration of avian reproductive effort: an integration of the ultimate and proximate bases for flexibility in clutch size, incubation behaviour, and yolk androgen deposition

Keith Sockman — 2007-06-13T10:26:50-00:00

Biological Reviews, Vol. 81, No. 4. (2006), pp. 629-666.

ABSTRACT How much effort to expend in any one bout of reproduction is among the most important decisions made by an individual that breeds more than once. According to life-history theory, reproduction is costly, and individuals that invest too much in a given reproductive bout pay with reduced reproductive output in the future. Likewise, investing too little does not maximize reproductive potential. Because reproductive effort relative to output can vary with predictable and unpredictable challenges and opportunities, no single level of reproductive effort maximizes fitness. This leads to the prediction that individuals possessing behavioural mechanisms to buffer challenges and take advantage of opportunities would incur fitness benefits. Here, we review evidence in birds, primarily of altricial species, for the presence of at least two such mechanisms and evidence for and against the seasonal coordination of these mechanisms through seasonal changes in plasma concentrations of the pituitary hormone prolactin. First, the seasonal decline in clutch size of most bird species may partially offset a predictable seasonal decline in the reproductive value of offspring. Second, establishing a developmental sibling-hierarchy among offspring may hedge against unpredictable changes in resource availability and offspring viability or quality, and minimize energy expenditure in raising a brood. The hierarchy may be a product, in part, of the timing of incubation onset relative to clutch completion and the rate of yolk androgen deposition during the laying cycle. Because clutch size should influence the effects of both these traits on the developmental hierarchy, we predicted and describe evidence in some species that females adjust the timing of incubation onset and rate of yolk androgen deposition to match clutch size. Studies on domesticated precocial species reveal an inhibitory effect of the pituitary hormone prolactin on egg laying, suggesting a possible hormonal basis for the regulation of clutch size. Studies on the American kestrel (Falco sparverius) and other species suggest that the seasonal increase in plasma concentrations of prolactin may regulate both a seasonal advance in the timing of incubation onset and a seasonal increase in the rate of yolk androgen deposition. These observations, together with strong conceptual arguments published previously, raise the possibility that a single hormone, prolactin, functions as the basis of a common mechanism for the seasonal adjustment of reproductive effort. However, a role for prolactin in regulating clutch size in any species is not firmly established, and evidence from some species indicates that clutch size may not be coupled to the timing of incubation onset and rate of yolk androgen deposition. A dissociation between the regulation of clutch size and the regulation of incubation onset and yolk androgen deposition may enable an independent response to the predictable and unpredictable challenges and opportunities faced during reproduction.

An evolutionary perspective on caching by corvids.

SR de Kort — 2007-06-13T10:26:35-00:00

Proc Biol Sci, Vol. 273, No. 1585. (22 February 2006), pp. 417-423.

A principal finding in the food-caching literature is that species differences in hoarding propensity are positively correlated with species differences in degree of adaptations to caching behaviour, such as performance on spatial memory tasks and hippocampal volume. However, there are examples that do not fit this pattern. We argue that these examples can be better understood by considering the phylogenetic relatedness between species. We reconstruct the ancestral state for caching behaviour in corvids and assess when transitions in caching behaviour occurred within the corvid phylogeny. Our analysis shows that the common ancestor of all corvids was a moderate cacher. This result suggests that corvids followed a bi-directional evolutionary trajectory in which caching was secondarily lost twice and there were at least two independent transitions from moderate to specialized caching. The independent evolution of specialized cachers in the two groups must, therefore, be a case of convergent evolution. This is exemplified by the fact that specialized cachers show structurally different adaptations serving the same function to intense caching, such as different pouches to transport food. Finally, we argue that convergent evolution may have led to adaptations in memory and hippocampus that serve the same function but differ in design, and that these different adaptations may explain the examples that do not fit the pattern predicted by the adaptive specialization hypothesis.

Approach-withdrawal behavior of peach-faced lovebirds, Agapornis roseicolis, and its modification by brain lesions.

R Phillips — 2007-06-13T10:21:28-00:00

Behaviour, Vol. 31, No. 1. (1968), pp. 163-184.

Biology of Birds of Paradise and Bowerbirds

Jared Diamond — 2007-07-01T04:19:32-00:00

Display dispersion and diet of birds of paradise: a comparison of nine species

Bruce Beehler — 2007-07-01T04:19:20-00:00

Behavioral Ecology and Sociobiology, Vol. 13, No. 3. (1983), pp. 229-238.

Birds of paradise (Paradisaeidae) are a diverse, poorly known group of tropical forest passerines. The majority of species (34 of 43) are sexually dimorphic, known or presumed to be promiscuous, and known to exhibit a range of male spacing patterns, from territoriality to lek behavior. In this study we mapped male dispersion in nine species of birds of paradise at three sites in Papua New Guinea. We observed four patterns: 1) Dispersed (territorial): Black-billed Sicklebill (Epimachus albertisi), Brown Sicklebill (E. meyeri), and Superb Bird of Paradise (Lophorina superba); 2) Dispersed (non-territorial): Magnificent Riflebird (Ptiloris magnificus), Magnificent Bird of Paradise (Diphyllodes magnificus), and Twelve-wired Bird of Paradise (Seleucidis melanoleuca); 3) Exploded lek: King Bird of Paradise (Cicinnurus reguis)-most males paired, and Lawes' Six-wired Bird of Paradise (Parotia lawesii); and 4) True lek: Raggiana Bird of Paradise (Paradisaea raggiana). These findings revise earlier assessments of spacing in some species, and the example of C. regius is the first documentation of a paired-male distribution for birds of paradise. In Table 3 we categorize all species of promiscuous birds of paradise into these four classes of dispersion. Comparison of diet with dispersion revealed a significant relationship between the extent of frugivory and the breakdown of widely-spaced territorial behavior. Obligate insectivores defended exclusive territories, while highly frugivorous species formed leks. Species with intermediate diets showed patterns of dispersion intermediate between these two extremes. Resource defense appears to be a viable option for species whose diet contains less than approximately 50% fruit.

How far do birds disperse seeds in the degraded tropical landscape of Hong Kong, China?

Weir — 2007-01-24T10:42:18-00:00

Landscape Ecology, Vol. 22, No. 1. (January 2007), pp. 131-140.

The persistence of ripe fleshy fruits in the presence and absence of frugivores

Alvin Tang — 2007-06-21T11:45:07-00:00

Oecologia, Vol. 142, No. 2. (17 January 2005), pp. 232-237.

A trade-off between antimicrobial defences and palatability to dispersers may place limits on fruit persistence in nature. The retention times of ripe fruits on 34 wild plant species under natural conditions (unbagged persistence) and when fruits had been bagged with nylon mesh to exclude frugivores (bagged persistence) were compared in Hong Kong, China (22°N). Bagged persistence is a measure of the effectiveness of fruit defence while unbagged persistence is an inverse measure of attractiveness to vertebrate frugivores. Bagged fruits persisted significantly longer than unbagged fruits in 30 species, with half the species tested persisting for more than 2 months. There was a significant positive relationship between the median persistence times of bagged and unbagged fruits, suggesting that species with a high resistance to microbial infection are also less attractive to frugivores. Both bagged and unbagged fruits persisted significantly longer at lower temperatures. There was a significant positive relationship between bagged persistence time and fibre content of the fruit pulp, but no significant relationships between unbagged persistence and the six fruit traits tested (diameter, pulp as a percentage of fruit fresh weight, and lipid, total soluble carbohydrate, nitrogen and fibre as percentages of pulp dry weight). Mechanical damage significantly decreased the bagged persistence time for half of the species. Although some fruits decayed or dried up while attached to the plant, fruits of 53% of the species remained visually attractive until they fell off.

Fig-eating by vertebrate frugivores: a global review.

M Shanahan — 2007-06-21T11:44:19-00:00

Biol Rev Camb Philos Soc, Vol. 76, No. 4. (November 2001), pp. 529-572.

The consumption of figs (the fruit of Ficus spp.: Moraceae) by vertebrates is reviewed using data from the literature, unpublished accounts and new field data from Borneo and Hong Kong. Records of frugivory from over 75 countries are presented for 260 Ficus species (approximately 30% of described species). Explanations are presented for geographical and taxonomic gaps in the otherwise extensive literature. In addition to a small number of reptiles and fishes, 1274 bird and mammal species in 523 genera and 92 families are known to eat figs. In terms of the number of species and genera of fig-eaters and the number of fig species eaten we identify the avian families interacting most with Ficus to be Columbidae, Psittacidae, Pycnonotidae, Bucerotidae, Sturnidae and Lybiidae. Among mammals, the major fig-eating families are Pteropodidae, Cercopithecidae, Sciuridae, Phyllostomidae and Cebidae. We assess the role these and other frugivores play in Ficus seed dispersal and identify fig-specialists. In most, but not all, cases fig specialists provide effective seed dispersal services to the Ficus species on which they feed. The diversity of fig-eaters is explained with respect to fig design and nutrient content, phenology of fig ripening and the diversity of fig presentation. Whilst at a gross level there exists considerable overlap between birds, arboreal mammals and fruit bats with regard to the fig species they consume, closer analysis, based on evidence from across the tropics, suggests that discrete guilds of Ficus species differentially attract subsets of sympatric frugivore communities. This dispersal guild structure is determined by interspecific differences in fig design and presentation. Throughout our examination of the fig-frugivore interaction we consider phylogenetic factors and make comparisons between large-scale biogeographical regions. Our dataset supports previous claims that Ficus is the most important plant genus for tropical frugivores. We explore the concept of figs as keystone resources and suggest criteria for future investigations of their dietary importance. Finally, fully referenced lists of frugivores recorded at each Ficus species and of Ficus species in the diet of each frugivore are presented as online appendices. In situations where ecological information is incomplete or its retrieval is impractical, this valuable resource will assist conservationists in evaluating the role of figs or their frugivores in tropical forest sites.

Frugivory and seed dispersal by vertebrates in the Oriental (Indomalayan) Region

Richard Corlett — 2007-06-21T11:43:58-00:00

Biological Reviews, Vol. 73, No. 4. (1998), pp. 413-448.

ABSTRACT Current knowledge of frugivory and seed dispersal by vertebrates in the Oriental Region is summarized. Some degree of frugivory has been reported for many fish and reptile species, almost half the genera of non-marine mammals and more than 40% of bird genera in the region. Highly frugivorous species, for which fruit dominates the diet for at least part of the year, occur in at least two families of reptiles, 12 families of mammals and 17 families of birds. Predation on seeds in fleshy fruits is much less widespread taxonomically: the major seed predators are colobine monkeys and rodents among the mammals, and parrots, some pigeons, and finches among the birds. Most seeds in the Oriental Region, except near its northern margins, are dispersed by vertebrate families which are endemic to the region or to the Old World. Small fruits and large, soft fruits with many small seeds are consumed by a wide range of potential seed dispersal agents, including species which thrive in small forest fragments and degraded landscapes. Larger, bigger-seeded fruits are consumed by progressively fewer dispersers, and the largest depend on a few species of mammals and birds which are highly vulnerable to hunting, fragmentation and habitat loss.

Effect of capsaicin upon afferent and efferent mechanisms of nociception and temperature regulation in birds.

H Sann — 2007-03-01T03:15:31-00:00

Can J Physiol Pharmacol, Vol. 65, No. 6. (June 1987), pp. 1347-1354.

(1) Acute capsaicin effects on nociception in the conscious chicken were tested by close arterial injection. The threshold dose to elicit nocifensive and autonomic responses was 50 micrograms, i.e., two to three orders of magnitude higher than in mammals but four times lower than in pigeons. (2) Foot withdrawal from hot water remained unchanged after capsaicin was injected either intravenously in the chicken at a cumulative dose of 600 mg/kg or perineurally at a dose of 100 micrograms into the sciatic nerve of pigeons. (3) Temperature regulation and body temperature in the chicken were not affected by subcutaneous injection of capsaicin, but intravenous infusion at rates of 2-5 or 10-13 mg X min-1 X kg-1 transiently lowered body temperature by 1.5 degrees C and stimulated panting and sometimes vasodilatation of the comb. Repeated capsaicin infusion produced temporary tachyphylaxia but no permanent desensitization. (4) A cumulative dose of 1 g/kg body weight capsaicin reduced the relationship between breathing frequency and respiratory evaporative heat loss in the duck. This deficit was compensated by more pronounced panting and, thus, did not indicate any impairment of temperature regulation. (5) Injection of capsaicin into the sciatic nerve depleted substance P in the dorsal horn of rats. Similar treatment in pigeons caused an increase of substance P immunoreactivity in the dorsal horn. (6) The effects of high capsaicin doses in birds indicate only low susceptibility of afferent neural mechanisms. Some of the effects may be due to a capsaicin action upon efferent neural mechanisms.

Distribution and binding sites of substance P and calcitonin gene-related peptide and their capsaicin-sensitivity in the spinal cord of rats and chicken: a comparative study.

W Rössler — 2007-03-05T00:34:04-00:00

Neuropeptides, Vol. 25, No. 4. (October 1993), pp. 241-253.

In a comparative study, the distribution and binding sites of substance P (SP) and calcitonin gene-related peptide (CGRP) in the spinal cord, and their susceptibility towards capsaicin pretreatment were studied in rats and chicken. Rats: In accordance with the SP immunohistochemistry, specific binding sites for 125I-Bolton-Hunter-SP were highest in laminae I-III. Binding sites for 125I-0Tyr-rat-CGRP were found to be dense around the central canal, moderate in the dorsal and weak in the ventral horn. Neonatal capsaicin pretreatment, that reduced SP and CGRP immunoreactivities, increased SP specific binding sites in laminae I-III and X by 20 and 100%, respectively. An increase in CGRP binding density was detected in laminae IV, V and in the lumbar ventral horn. Displacement studies revealed a significant decrease of EC50-values for SP. Chicken: SP and CGRP immunoreactivities and SP specific binding sites were distributed similarly as in rats. Binding sites for radiolabelled CGRP, however, were highest in lamina X and in the ventral horn. Capsaicin (800 mg/kg) injected into the eggs 9 days before hatching had no influence on growth rate, nociception, peptide immunoreactivities and binding of the respective radioligands. The data demonstrated a different action of capsaicin on SP and CGRP and their specific binding sites in the spinal cord of rats and chicken and were discussed with regard to functional differences between these two animal species.

Nociception in pigeons is not impaired by capsaicin.

J Szolcsányi — 2007-03-01T03:12:15-00:00

Pain, Vol. 27, No. 2. (November 1986), pp. 247-260.

In order to examine the sensitivity of the nociceptive system of birds to capsaicin, the algesic potency of the drug was compared with that of veratridine and mustard oil by instillation into the eye of conscious pigeons and guinea-pigs. In guinea-pigs, 10(-6) g/ml capsaicin provoked severe protective reactions, but even high concentrations of 10(-2) g/ml were insufficient in pigeons. Veratridine and mustard oil induced similar reactions in both species. Close arterial injections of algesic substances revealed that the threshold dose of capsaicin for cardiovascular and nocifensive reactions was 10,000-fold higher in pigeons (200 micrograms) than in guinea-pigs (0.02 micrograms). All other algesic substances tested (bradykinin, 5-HT, veratridine and KCl) had similar thresholds in both species. Slow infusion of a total dose of 600 mg/kg capsaicin into the radial artery of pigeons did not alter the sensitivity to any of the algesic substances tested, which demonstrates that even high concentrations of capsaicin have no desensitizing effect. The demonstrated insensitivity of pigeons to the algesic effect of capsaicin is discussed in the context of the inability of the drug to deplete substance P (SP) from afferent terminals in the spinal cord of the pigeon.

Seed dispersal. Directed deterrence by capsaicin in chilies.

JJ Tewksbury — 2007-03-01T03:11:20-00:00

Nature, Vol. 412, No. 6845. (26 July 2001), pp. 403-404.

The primary function of ripe, fleshy fruit is to facilitate seed dispersal by attracting consumers, yet many fruits contain unpleasant-tasting chemicals that deter consumption by vertebrates. Here we investigate this paradox in the chili (Capsicum) and find that capsaicin, the chemical responsible for the fruit's peppery heat, selectively discourages vertebrate predators without deterring more effective seed dispersers.

Molecular Basis for Species-Specific Sensitivity to "Hot" Chili Peppers

Sven-Eric Jordt — 2007-03-01T03:07:45-00:00

Cell, Vol. 108, No. 3. (8 February 2002), pp. 421-430.

Chili peppers produce the pungent vanilloid compound capsaicin, which offers protection from predatory mammals. Birds are indifferent to the pain-producing effects of capsaicin and therefore serve as vectors for seed dispersal. Here, we determine the molecular basis for this species-specific behavioral response by identifying a domain of the rat vanilloid receptor that confers sensitivity to capsaicin to the normally insensitive chicken ortholog. Like its mammalian counterpart, the chicken receptor is activated by heat or protons, consistent with the fact that both mammals and birds detect noxious heat and experience thermal hypersensitivity. Our findings provide a molecular basis for the ecological phenomenon of directed deterrence and suggest that the capacity to detect capsaicin-like inflammatory substances is a recent acquisition of mammalian vanilloid receptors.

Some like it hot

Karin Romisch — 2007-03-01T03:02:42-00:00

Trends in Biochemical Sciences, Vol. 27, No. 4. (1 April 2002), 174.

The Songbird Neurogenomics (SoNG) Initiative: community-based tools and strategies for study of brain gene function and evolution

Kirstin Replogle — 2008-03-19T00:14:12-00:00

BMC Genomics, Vol. 9, No. 1. (2008)

BACKGROUND:Songbirds hold great promise for biomedical, environmental and evolutionary research. A complete draft sequence of the zebra finch genome is imminent, yet a need remains for application of genomic resources within a research community traditionally focused on ethology and neurobiological methods. In response, we developed a core set of genomic tools and a novel collaborative strategy to probe gene expression in diverse songbird species and natural contexts.RESULTS:We end-sequenced cDNAs from zebra finch brain and incorporated additional sequences from community sources into a database of 86,784 high quality reads. These assembled into 31,658 non-redundant contigs and singletons, which we annotated via BLAST search of chicken and human databases. The results are publicly available in ESTIMA:Songbird. We produced a spotted cDNA microarray with 20,160 addresses representing 17,214 non-redundant products of an estimated 11,500-15,000 genes, validating it by analysis of immediate-early gene (zenk) gene activation following song exposure and by demonstrating effective cross hybridization to genomic DNAs of other songbird species in the Passerida Parvorder. Our assembly was also used in the design of the "Lund-zfa" Affymetrix array representing ~22,000 non-redundant sequences. When the two arrays were hybridized to cDNAs from the same set of male and female zebra finch brain samples, both arrays detected a common set of regulated transcripts with a Pearson correlation coefficient of 0.895. To stimulate use of these resources by the songbird research community and to maintain consistent technical standards, we devised a aCommunity Collaborationa mechanism whereby individual birdsong researchers develop experiments and provide tissues, but a single individual in the community is responsible for all RNA extractions, labelling and microarray hybridizations.CONCLUSIONS:Immediately, these results set the foundation for a coordinated set of 25 planned experiments by 16 research groups probing fundamental links between genome, brain, evolution and behavior in songbirds. Energetic application of genomic resources to research using songbirds should help illuminate how complex neural and behavioral traits emerge and evolve.

Phylogenetic distributions of British birds of conservation concern

Gavin Thomas — 2008-06-12T00:03:19-00:00

Proceedings of the Royal Society B: Biological Sciences

Recent studies suggest that species' life histories and ecology can be used to forecast future extinction risk. Threatened species often share similar traits such that if a trait predisposing a species to decline or extinction is evolutionarily conserved, then close relatives of threatened species are themselves likely to be at risk. The phylogenetic distribution of current threat has been argued to provide insight into the species that could be threatened in the future when trait data are not available. Conservation criteria are typically based on multiple indices that capture different symptoms of threat including population trends and range contraction. However, there is no reason to assume consistent phylogenetic distributions of different symptoms. I construct a molecular phylogeny of 249 species of British birds (more than 93% of the breeding and wintering species) and use this to show that the species that are threatened due to population declines are phylogenetically more closely related than expected by chance alone. However, species that are listed for other reasons, including range contraction, are distributed randomly with respect to phylogeny. I suggest that while phylogeny can be informative with respect to identifying clades that are susceptible to some measures of extinction risk, such patterns are likely to be idiosyncratic with respect to symptom and taxa.

A Phylogenomic Study of Birds Reveals Their Evolutionary History

Shannon Hackett — 2008-06-26T23:34:26-00:00

Science, Vol. 320, No. 5884. (27 June 2008), pp. 1763-1768.

Deep avian evolutionary relationships have been difficult to resolve as a result of a putative explosive radiation. Our study examined [~]32 kilobases of aligned nuclear DNA sequences from 19 independent loci for 169 species, representing all major extant groups, and recovered a robust phylogeny from a genome-wide signal supported by multiple analytical methods. We documented well-supported, previously unrecognized interordinal relationships (such as a sister relationship between passerines and parrots) and corroborated previously contentious groupings (such as flamingos and grebes). Our conclusions challenge current classifications and alter our understanding of trait evolution; for example, some diurnal birds evolved from nocturnal ancestors. Our results provide a valuable resource for phylogenetic and comparative studies in birds. 10.1126/science.1157704

Action imitation in birds.

TR Zentall — 2005-12-19T22:23:11-00:00

Learn Behav, Vol. 32, No. 1. (February 2004), pp. 15-23.

Action imitation, once thought to be a behavior almost exclusively limited to humans and the great apes, surprisingly also has been found in a number of bird species. Because imitation has been viewed by some psychologists as a form of intelligent behavior, there has been interest in how it is distributed among animal species. Although the mechanisms responsible for action imitation are not clear, we are now at least beginning to understand the conditions under which it occurs. In this article, I try to identify and differentiate the various forms of socially influenced behavior (species-typical social reactions, social effects on motivation, social effects on perception, socially influenced learning, and action imitation) and explain why it is important to differentiate imitation from other forms of social influence. I also examine some of the variables that appear to be involved in the occurrence of imitation. Finally, I speculate about why a number of bird species, but few mammal species, appear to imitate.

Reconstructing the evolution of the respiratory apparatus in tetrapods.

SF Perry — 2005-03-20T03:30:15-00:00

Respir Physiol Neurobiol, Vol. 144, No. 2-3. (15 December 2004), pp. 125-139.

The structural type of a lung for animals that are derived from a single ancestral group can be characterized using extant phylogenetic bracketing. Functional morphological approximation can then be used to provide further information on the functional attributes. Combining information from diverse sources, plausible explanations are deduced for the respiratory apparatus of extinct species. The air-breathing apparatus of tetrapods has its origin in gill breathing. The lungs of the first tetrapods were probably long and consisted of a single series of parenchyma-filled chambers, arranged along an intrapulmonary duct. The duct gave rise to a broad central lumen in anurans. In amniotes a cartilaginous reinforcement evolved. The septate nature of the gas-exchange tissue (parenchyma) is recognizable in all tetrapods except birds. Active expiration began with the origin of transverse body wall musculature in amphibians, whereas active, negative-pressure inspiration is seen only in amniotes. The functional transition of trunk musculature from locomotor to respiratory is most complete in birds.

Further spread of avian influenza in Europe, detection in French farmed birds and German cat.

2006-07-01T00:13:05-00:00

Euro Surveill, Vol. 11, No. 3. (March 2006)

Tenth EU country detects highly pathogenic avian influenza in wild birds.

2006-07-01T00:11:56-00:00

Euro Surveill, Vol. 11, No. 3. (March 2006)

Pattern filtering for detection of neural activity, with examples from HVc activity during sleep in zebra finches.

Z Chi — 2006-08-17T20:13:48-00:00

Neural Comput, Vol. 15, No. 10. (October 2003), pp. 2307-2337.

The detection of patterned spiking activity is important in the study of neural coding. A pattern filtering approach is developed for pattern detection under the framework of point processes, which offers flexibility in combining temporal details and firing rates. The detection combines multiple steps of filtering in a coarse-to-fine manner. Under some conditional Poisson assumptions on the spiking activity, each filtering step is equivalent to classifying by likelihood ratios all the data segments as targets or as background sequences. Unlike previous studies, where global surrogate data were used to evaluate the statistical significance of the detected patterns, a localized p-test procedure is developed, which better accounts for firing modulation and nonstationarity in spiking activity. Common temporal structures of patterned activity are learned using an entropy-based alignment procedure, without relying on metrics or pair-wise alignment. Applications of pattern filtering to single, presumptive interneurons recorded in the nucleus HVc of zebra finch are illustrated. These demonstrate a match between the auditory-evoked response to playback of the individual bird's own song and spontaneous activity during sleep. Small temporal compression or expansion, or both, is required for optimal matching of spontaneous patterns to stimulus-evoked activity.

Genetically-based plant resistance traits affect arthropods, fungi, and birds

Lara Dickson — 2008-06-17T16:11:24-00:00

Oecologia, Vol. 106, No. 3. (1 May 1996), pp. 400-406.

We examine how the distribution of a leafgalling aphid (Pemphigus betae) affects other species associated with natural stands of hybrid cottonwoods (Populus angustifolia x P. fremontii). Aphid transfers on common-garden clones and RFLP analysis show that resistance to aphids in cottonwoods is affected by plant genotype. Because susceptible trees typically support thousands of galls, while adjacent resistant trees have few or none, plant resistance traits that affect the distribution of this abundant herbivore may directly and/or indirectly affect other species. We found that the arthropod community of aphid-susceptible trees had 31% greater species richness and 26% greater relative abundance than aphid-resistant trees. To examine direct and indirect effects of plant resistance traits on other organisms, we experimentally excluded aphids and found that abundances and/or foraging behavior of arthropods, fungi, and birds were altered. First, exclusion of gall aphids on susceptible trees resulted in a 24% decrease in species richness and a 28% decrease in relative abundance of the arthropod community. Second, exclusion of aphids also caused a 2- to 3-fold decrease in foraging and/or presence of three taxa of aphid enemies: birds, fungi, and insects. Lastly, aphidexclussion resulted in a 2-fold increase in inquilines (animals who live in abodes properly belonging to another). We also found that fungi and birds responded to variation in gall density at the branch level. We conclude plant resistance traits affect diverse species from three trophic levels supporting a “bottom-up” influence of plants on community structure.

Recursive syntactic pattern learning by songbirds

Timothy Gentner — 2006-04-26T16:37:15-00:00

Nature, Vol. 440, No. 7088., pp. 1204-1207.

Fractal dimension of birds population sizes time series

Alfonso Garmendia — 2007-06-04T15:18:53-00:00

Mathematical Biosciences, Vol. 206, No. 1. (March 2007), pp. 155-171.

Information about fractal dimension is collected so that it can be applied to time series interpreting Hurst coefficient. The population size of a species is modelled as a dynamic system. The Hurst coefficient is calculated for these times series. A computer programme has been elaborated to compute the Hurst exponent of time series using the algorithms of range increment, second order moment increment and local second order moment increment. It has been applied to time series of birds' populations.

Speciation in birds: genes, geography, and sexual selection.

SV Edwards — 2006-03-29T10:44:53-00:00

Proc Natl Acad Sci U S A, Vol. 102 Suppl 1 (3 May 2005), pp. 6550-6557.

Molecular studies of speciation in birds over the last three decades have been dominated by a focus on the geography, ecology, and timing of speciation, a tradition traceable to Mayr's Systematics and the Origin of Species. However, in the recent years, interest in the behavioral and molecular mechanisms of speciation in birds has increased, building in part on the older traditions and observations from domesticated species. The result is that many of the same mechanisms proffered for model lineages such as Drosophila--mechanisms such as genetic incompatibilities, reinforcement, and sexual selection--are now being seriously entertained for birds, albeit with much lower resolution. The recent completion of a draft sequence of the chicken genome, and an abundance of single-nucleotide polymorphisms on the autosomes and sex chromosomes, will dramatically accelerate research on the molecular mechanisms of avian speciation over the next few years. The challenge for ornithologists is now to inform well studied examples of speciation in nature with increased molecular resolution-to clone speciation genes if they exist--and thereby evaluate the relative roles of extrinsic, intrinsic, deterministic, and stochastic causes for avian diversification.

A Mitogenomic Timescale for Birds Detects Variable Phylogenetic Rates of Molecular Evolution and Refutes the Standard Molecular Clock

Sergio Pereira — 2006-08-02T10:15:31-00:00

Mol Biol Evol, Vol. 23, No. 9. (1 September 2006), pp. 1731-1740.

Current understanding of the diversification of birds is hindered by their incomplete fossil record and uncertainty in phylogenetic relationships and phylogenetic rates of molecular evolution. Here we performed the first comprehensive analysis of mitogenomic data of 48 vertebrates, including 35 birds, to derive a Bayesian timescale for avian evolution and to estimate rates of DNA evolution. Our approach used multiple fossil time constraints scattered throughout the phylogenetic tree and accounts for uncertainties in time constraints, branch lengths, and heterogeneity of rates of DNA evolution. We estimated that the major vertebrate lineages originated in the Permian; the 95% credible intervals of our estimated ages of the origin of archosaurs (258 MYA), the amniote-amphibian split (356 MYA), and the archosaur-lizard divergence (278 MYA) bracket estimates from the fossil record. The origin of modern orders of birds was estimated to have occurred throughout the Cretaceous beginning about 139 MYA, arguing against a cataclysmic extinction of lineages at the Cretaceous/Tertiary boundary. We identified fossils that are useful as time constraints within vertebrates. Our timescale reveals that rates of molecular evolution vary across genes and among taxa through time, thereby refuting the widely used mitogenomic or cytochrome b molecular clock in birds. Moreover, the 5-Myr divergence time assumed between 2 genera of geese (Branta and Anser) to originally calibrate the standard mitochondrial clock rate of 0.01 substitutions per site per lineage per Myr (s/s/l/Myr) in birds was shown to be underestimated by about 9.5 Myr. Phylogenetic rates in birds vary between 0.0009 and 0.012 s/s/l/Myr, indicating that many phylogenetic splits among avian taxa also have been underestimated and need to be revised. We found no support for the hypothesis that the molecular clock in birds "ticks" according to a constant rate of substitution per unit of mass-specific metabolic energy rather than per unit of time, as recently suggested. Our analysis advances knowledge of rates of DNA evolution across birds and other vertebrates and will, therefore, aid comparative biology studies that seek to infer the origin and timing of major adaptive shifts in vertebrates. 10.1093/molbev/msl038

Hummingbird Behavior and Mechanisms of Selection on Flower Color in Ipomopsis

Elvia Melendez-Ackerman — 2006-02-26T23:07:09-00:00

Ecology, Vol. 78, No. 8. (1997), pp. 2532-2541.

Apparent associations between flower color and type of pollinator might be explained by correlations between color and other floral traits, rather than by narrow pollinator preferences for color. To explore this possibility, we obtained flowers varying naturally in color, nectar reward, and morphology, from a hybrid zone between Ipomopsis aggregata and I. tenuituba in western Colorado, United States. We used aviary and field experiments to study preferences of hummingbirds for unmanipulated flowers and for flowers in which we experimentally dissociated color from nectar reward and morphology. Hummingbirds preferred red flowers of I. aggregata, which contain superior nectar rewards and have relatively broad corolla tubes, relative to flowers of I. tenuituba, which are white, contain small nectar rewards, and have narrow tubes. There was no evidence of flower constancy. When presented with flowers differing only in color, birds showed a spontaneous preference for red. However, this preference could be reversed by making white flowers more rewarding than red. When plants of both parental species and their hybrids were placed in an array in the field, with all flowers painted red, hummingbirds preferred to visit the more rewarding, wider tubed I. aggregata. These results suggest that pollinator-mediated selection could act on color, shape, and nectar separately. Experimental manipulations that dissociate these traits are essential to distinguish direct from correlated selection. Also, hummingbird selection favoring red flowers may result from past experience and, thus, may depend on the ecological context.

Sexual Selection and Taxonomic Diversity in Passerine Birds

Timothy Barraclough — 2006-03-27T22:32:11-00:00

Proceedings: Biological Sciences, Vol. 259, No. 1355. (1995), pp. 211-215.

Many authors have suggested that sexual selection by female choice may increase the speciation rate and hence generate taxonomic diversity. Using sister taxa comparisons, we find a significant positive correlation between the proportion of sexually dichromatic species within taxa of passerine birds, and the number of species in those taxa. Theory predicts this result if sexual dichromatism in passerines has evolved through the action of female choice.

Metabolic rate, generation time, and the rate of molecular evolution in birds.

AO Mooers — 2006-03-27T22:29:33-00:00

Mol Phylogenet Evol, Vol. 3, No. 4. (December 1994), pp. 344-350.

A recent hypothesis suggests that resting metabolic rate, measured as energy expended per unit body mass per unit time, might be implicated in the rate of nucleotide substitution in animals. Using relative rate tests on DNA-DNA hybridization data from birds, we show that generation time is significantly correlated with genetic distance between members of an ingroup and an outgroup taxon, but that neither metabolic rate nor body mass explain variation consistent with the hypothesis, either alone or with generation time.

On the origin of brood parasitism in altricial birds

Yoram Yom-Tov — 2006-02-07T19:30:57-00:00

Behavioral Ecology, Vol. 17, No. 2. (March 2006), pp. 196-205.

Patterns of genetic variation in the adaptive radiation of New World crossbills (Aves: Loxia)

N Parchma — 2006-05-13T20:36:47-00:00

Molecular Ecology, Vol. 15, No. 7. (June 2006), pp. 1873-1887.

Differentiation of avian poxvirus strains on the basis of nucleotide sequences of 4b gene fragment.

D Lüschow — 2006-05-28T05:19:53-00:00

Avian Dis, Vol. 48, No. 3. (September 2004), pp. 453-462.

Investigations for detection and differentiation of nine avian poxviruses (APVs) were carried out by the use of a polymerase chain reaction (PCR) combined with restriction enzyme analysis (REA) and further nucleotide sequence analysis. With one primer set, which framed a region within the fowl poxvirus 4b core protein gene, we were able to detect APV-specific DNA from 19 tested strains and isolates belonging to five defined Avipoxvirus species and four previously undefined isolated species. PCR results revealed no recognizable differences in size of amplified fragments among the different APVs. REA of PCR products with MseI and EcoRV allowed us to differentiate most of the tested avipox species. Nucleotide sequence analysis of the amplified fragments showed a nucleotide similarity of 72%-100% among the different species. Phylogenetic analysis documented five distinguishable sequence clusters in accordance with results obtained by REA. PCR in combination with REA and sequencing of the amplified fragments is a rapid and effective diagnostic system, and it is a new approach to refine epidemiologic studies of APV infections.