Fidelity to Bowers, Adult Plumage Acquisition, Longevity and Survival in Male Golden BowerbirdsPrionodura newtoniana

2000 ◽  
Vol 100 (4) ◽  
pp. 249-263
Author(s):  
Clifford B. Frith ◽  
Dawn W. Frith
Keyword(s):  
Adult Plumage

Ecological Studies of the Black Swan II*. Colour and Plumage Changes, Growth rates, Sexual Maturation and Timing and Frequency of Breeding

1981 ◽  
Vol 8 (1) ◽  
pp. 121 ◽  
Author(s):  
LW Braithwaite
Keyword(s):  
Sexual Maturation ◽  
Growth Rates ◽  
Sexual Maturity ◽  
Temporal Relationship ◽  
Breeding Birds ◽  
Black Swan ◽  
Ecological Studies ◽  
Single Female ◽  
Adult Plumage ◽  
One Year

Aspects of the biology of the black swan were obtained mainly from studies of captive birds. Details are given on colour and plumage; the distinctive juvenile and adult plumages are described; in adults iris colour differs between the sexes and is related to weight in both sexes and sexual condition in males Growth rates vary significantly according to environment. Fledging was at 108-141 days for captive cygnets but was estimated to extend to 170 days in wild birds. Young birds usually moulted into adult plumage between August and November at ages of 8-26 months. Replacement of the wing plumage requires 38-51 days. Periods of 7-36 months elapse between moults of the wing plumage, the period decreasing significantly wlth age. There is no fixed temporal relationship between breeding and moulting, though adults often moult within six months of laying, so that they are flightless during the pre-fledging period of cygnets. Breeding birds tend to moult later in the year and more frequently than birds not breeding. Birds usually attain sexual maturity and breed at ages of 18-24 or 33-36 months, within 1-2 years of attainment of adult plumage. Captive swans bred in all months of the year except December and January, with most in June-August. Frequency of laying was variable and highly dependent on the particular circumstances of captivity. Most swans commenced two or more clutches annually in at least one year of captivity. Within less than 12 months, a single female was capable of commencing eight clutches or rearing three broods.

scholarly journals Comparative morphometric evaluation of hepatic hemosiderosis in wild Magellanic penguins (Spheniscus magellanicus) infected with different Plasmodium spp. subgenera

2019 ◽  
Vol 28 (1) ◽  
pp. 68-79
Author(s):  
Ana Carolina Ewbank ◽  
Ricardo de Francisco Strefezzi ◽  
Carlos Sacristán ◽  
Cristiane Kiyomi Miyaji Kolesnikovas ◽  
Aryse Martins ◽  
...  
Keyword(s):  
Avian Malaria ◽  
Iron Supplementation ◽  
Oil Contamination ◽  
Rehabilitation Center ◽  
Liver Mass ◽  
Spheniscus Magellanicus ◽  
Age Class ◽  
Magellanic Penguins ◽  
Adult Plumage ◽  
Morphometric Evaluation

Abstract Avian malaria is one of the most important diseases of captive penguins. We employed morphometric techniques to evaluate hepatic hemosiderosis in rehabilitating wild Magellanic penguins (Spheniscus magellanicus) that were negative (n = 9) or naturally infected by different subgenera of Plasmodium spp. (n = 24), according with: Plasmodium subgenera (Haemamoeba, Huffia, Other lineages, and Unidentified lineages), severity of Plasmodium histopathological lesions, and concurrent diseases, age class (juvenile or adult plumage), sex (male, female or not determined), body score (emaciated, thin, good, excellent, not available), molt, presence or absence of oil contamination upon admission, iron supplementation, and rehabilitation center. The percentage of the area occupied by hemosiderin was called ‘Index of Hepatic Hemosiderosis (IHH)’. Plasmodium-positive females presented significantly higher IHH values (17.53 ± 12.95%) than males (7.20 ± 4.25%; p = 0.041). We observed higher levels of congestion (p = 0.0182) and pneumonia (p = 0.0250) severity between Unidentified lineages vs. Huffia. We believe that the hepatic hemosiderosis observed in this study was multifactorial, the result of pathological processes caused by malaria, molting, hemoglobin and myoglobin catabolism during migration, anemia, concomitant diseases, and iron supplementation, all possibly potentiated by decreased liver mass. Further studies are needed to clarify the mechanisms of these hypotheses.

scholarly journals Integrative taxonomy of the Changeable Hawk-Eagle Nisaetus cirrhatus complex (Accipitriformes: Accipitridae) in India

Zootaxa ◽  
2020 ◽  
Vol 4789 (2) ◽  
pp. 554-574 ◽  
Author(s):  
J. O. GJERSHAUG ◽  
O. H. DISERUD ◽  
O. KLEVEN ◽  
P. C. RASMUSSEN ◽  
Y. ESPMARK
Keyword(s):  
Gene Flow ◽  
Reproductive Isolation ◽  
Current Knowledge ◽  
Integrative Taxonomy ◽  
Restricted Gene Flow ◽  
Northern Plains ◽  
Adult Plumage ◽  
Himalayan Foothills ◽  
Taxonomic Approach ◽  
Crest Length

The Changeable Hawk-Eagle Nisaetus cirrhatus complex is represented by two taxa in mainland India: N. c. cirrhatus in the northern plains and peninsula and N. c. limnaeetus in the Himalayan foothills. Traditionally these taxa have been regarded as subspecies of one species, but recently they have been proposed to be different species. Here, we use an integrative taxonomic approach based on considerations of plumage, biometrics, genetics and vocalizations. Several plumage characters are significantly different between the two taxa, but crest length was the only one of 56 characters that was diagnostically different, with no overlap. About 30% of the birds had intermediate crest lengths, suggesting that they are hybrids or backcrosses, as also supported by the microsatellite results. PCAs of adult plumage show many intermediate individuals, irrespective of whether these birds were collected near a putative contact zone. There is restricted gene flow between the two taxa, presumably as a result of their largely allopatric distributions. On current knowledge, reproductive isolation appears to be weak at best, and we therefore recommend continuing to regard limnaeetus and cirrhatus as conspecific. 

scholarly journals Studies on the relation of gonadic structure to plumage characterisation in the domestic fowl.—I. Henny-feathering in an ovariotomised hen with active testis grafts

1926 ◽  
Vol 99 (696) ◽  
pp. 232-241 ◽  
Keyword(s):  
Domestic Fowl ◽  
Ovarian Tissue ◽  
Testicular Tissue ◽  
The Body ◽  
Endocrine Function ◽  
Ovarian Hormone ◽  
Adult Plumage ◽  
Structural Differences ◽  
The Individual ◽  
Considerable Body

In certain breeds and varieties of the domestic fowl, e. g ., the Brown Leghorn, the adult plumage presents a sexual dimorphism in the kind and distribution of colour in the individual feathers, and in one or more of the seven areas in which plumage colour differences may distinguish breed from breed, and variety from variety, and also in the structure of the feathers of the neck and saddle hackles, and by the presence of the large tail sickles of the male. In other cases, such as the White Leghorn, the sexes are to be distinguished only by the structural differences in the hackle feathers and by the large tail sickles of the male. In the case of certain other breeds, the Campines and the Sebrights, for example, the plumage of the male is identical with that of the female both in colouration and in structure. Cocky-feathering in the case of such varieties as the Brown and the White Leghorns can be regarded as a trustworthy indication that within the body there is, or was at the time when the plumage was developed, active functional testicular tissue; henny-feathering as an indication that there is, or was when the plumage was developed, active functional ovarian tissue. Gonadectomy in both sexes is followed after a moult by the assumption of a plumage which has the colouration of that of the male of the variety to which the bird belongs, whilst the barbules in the distal portions of the feathers of the hackle regions are absent, also a characteristic of the cocky-feathered male, but the plumage is much looser and far more luxuriant in its growth ; the plumage characters of the capon and of the poularde are exactly alike. Since this is the case, it is commonly argued that the gonads exhibit an endocrine function, the ovarian hormone possessing the faculty of inhibiting the development of cocky-feathering. The fact that in the Campine and the Sebright the cock is also hennyfeathered is explained on the assumption that in their functioning the testes of such a male are equivalent endocrinologically to the ovary of a hen. Such an interpretation is supported by the facts that castration of the normally henny-feathered cock is followed by the assumption of typical cocky-feathering ; that castration of the normally cocky-feathered male and subsequent successful ovarian implantation is followed by the development of henny-feathering; and that, in such cases as have so far been recorded, successful testicular implantation in an ovariotomised hen has been followed by the development of a plumage of the cock (as opposed to that of the capon or poularde). There is undoubtedly a considerable body of evidence, secured from careful experimentation, that supports the endocrine interpretation of the relations between gonad structure and plumage characterisation, and most biologists have accepted this interpretation. However, there are several facts concerning the fowl that cannot easily be reconciled to this hypothesis. The case about to be discussed in our opinion, severely questions its validity.

scholarly journals White-Tailed Sea Eagle (Haliaeetus Albicilla) Die-Off due to Infection with Highly Pathogenic Influenza Virus, Subtype H5N8, in Germany

2018 ◽  
Author(s):  
Oliver Krone ◽  
Anja Globig ◽  
Reiner Ulrich ◽  
Timm Harder ◽  
Jan Schinköthe ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Kidney Tissue ◽  
Mortality Factor ◽  
Protected Species ◽  
Fatal Disease ◽  
Highly Pathogenic ◽  
Haliaeetus Albicilla ◽  
Adult Plumage ◽  
First Time ◽  
Virus Subtype

In contrast to previous incursions of highly pathogenic H5 viruses, H5N8 clade 2.3.4.4b caused numerous lethal infections in white-tailed sea eagles (Haliaeetus albicilla) in Germany during the winter 2016/2017. Until April 2017, 17 HPAIV H5N8-positive white-tailed sea eagles had been detected (three alive and 14 dead). Mainly young eagles died (before reaching the adult plumage at 5 years), often with severe neurological symptoms, where histopathology revealed mild to moderate, oligo- to multifocal necrotizing polioencephalitis. Lethal lead (Pb) concentrations, proven as main mortality factor of the sea eagles could be ruled out since values measured in liver or kidney tissue were all within background levels (< 1 ppm). Since the fall of 2016, the epizootic of HPAIV H5 clade 2.3.4.4b reportedly induced, for the first time, fatal disease in European white-tailed see eagles. The virus strain may become a new threat to a highly protected species across its distribution range in Eurasia. Positive cloacal swaps have proven that the eagles can spread the virus with their faeces.

Sexual maturation in starlings raised on long or short days: changes in hypothalamic gonadotrophin-releasing hormone and plasma LH concentrations

1989 ◽  
Vol 123 (2) ◽  
pp. 189-196 ◽  
Author(s):  
A. Dawson ◽  
A. R. Goldsmith
Keyword(s):  
Sexual Maturation ◽  
Releasing Hormone ◽  
Short Day ◽  
Nest Boxes ◽  
Adult Plumage ◽  
Gonadotrophin Releasing Hormone ◽  
Testicular Size ◽  
Induced Changes ◽  
Short Days

ABSTRACT Is the extended prepubertal period which occurs in most birds due to a juvenile photorefractoriness analogous to photorefractoriness in adults? Starlings were taken from nest boxes 4 days after hatching and hand-reared on long days or short days. In females on long days, hypothalamic gonadotrophin-releasing hormone (GnRH) content and plasma LH concentration remained low. In intact males on long days, plasma LH remained low and the testes remained small, and in castrated birds, plasma LH also remained low. In females reared on short days, hypothalamic GnRH content began to increase dramatically from 4 weeks of age and plasma LH increased from 6 weeks of age. In intact males on short days, there was a slight increase in plasma LH and testicular size, and in castrated males, plasma LH increased markedly from six weeks of age. All birds on long days moulted into adult plumage, whereas those on short days retained juvenile plumage. The changes in birds reared on short days were similar to those found when photorefractory adult birds are transferred to short days. This adds to the evidence that juvenile photorefractoriness is analogous to photorefractoriness in adults, and therefore that the seasonal termination of photorefractoriness is an annual puberty. However, the responses to short days occur later in birds raised on short days than in older birds transferred to short days, which suggests either that short day-induced changes occur more slowly in young birds, or that birds only respond to short days after a certain age. Journal of Endocrinology (1989) 123, 189–196

scholarly journals Cryptic Dichromatism and Seasonal Color Variation in the Diademed Tanager

The Condor ◽  
2005 ◽  
Vol 107 (3) ◽  
pp. 648-656 ◽  
Author(s):  
Pablo L. Tubaro ◽  
Dario A. Lijtmaer ◽  
Stephen C. Lougheed
Keyword(s):  
Short Wave ◽  
Spectral Shape ◽  
Color Variation ◽  
Plumage Color ◽  
Body Regions ◽  
Adult Plumage ◽  
Components Analysis ◽  
Almost All ◽  
Dark Blue ◽  
Plumage Reflectance

Abstract We studied the patterns of sexual dichromatism and seasonal variation in plumage color in the Diademed Tanager (Stephanophorus diadematus), a species previously considered devoid of variation in adult plumage. The general coloration of this species is dark blue-violet, with a white-blue and red crown. Plumage reflectance of seven body regions from 33 study skins belonging to adults of both sexes was measured. Reflectance values were used in a principal components analysis (PCA) and hue, short-wave chroma, and UV chroma were also measured directly on the spectra. Both PCA factor scores and these latter variables were subjected to two-way ANCOVAs with sex and season as main factors and the year of capture as a covariate. We found that crowns of males were significantly brighter than those of females. In addition, the nape, chest, and belly showed significant differences in spectral shape, with relatively greater short-wave reflectance and less long-wave reflectance in males than in females. Although sexes were alike in hue, they differed in chroma in almost all body regions. Brightness also differed between seasons, and contrary to our expectation nonbreeding birds were brighter than breeding ones. This result may be a consequence of the particular molt program of tanagers that includes only a complete post-reproductive molt. Despite finding seasonal differences in spectral shape in various body regions, no significant changes in hue, short-wave chroma, or UV chroma were evident. To our knowledge, this is the first report of variation in adult plumage color for the Diademed Tanager, and we suggest that dichromatism in tanagers may be even more pervasive than is currently recognized. Dicromatismo Críptico y Variación Estacional de Color en Stephanophorus diadematus Resumen. Estudiamos los patrones de dicromatismo sexual y variación estacional en la coloración del plumaje de Stephanophorus diadematus, una especie previamente considerada carente de variación en la coloración del plumaje adulto. La coloración general de esta especie es azul violáceo oscuro, con una corona blanca azulada y roja. Se midió la reflectancia de siete regiones corporales en 33 pieles de estudio pertenecientes a adultos de ambos sexos. Los valores de reflectancia se utilizaron en un análisis de componentes principales, y además se midieron el tono (hue), la intensidad del color de onda corta y la intensidad del color de UV directamente sobre los espectros. Tanto los factores del análisis de componentes principales como las variables mencionadas fueron sujetos a ANCOVAs de dos factores, considerando el sexo y la estación como factores principales, y el año de captura como covariable. Estos análisis mostraron que la corona de los machos es significativamente más brillante que la de las hembras. Además, la nuca, el pecho y el vientre mostraron diferencias significativas en la forma espectral, presentando los machos mayor reflectancia en la zona de onda corta y menor en la zona de onda larga que las hembras. Si bien el tono no difirió entre sexos, la intensidad del color difirió en la mayoría de las regiones corporales entre machos y hembras. El brillo también difirió entre temporadas y, contrariamente a nuestra expectativa, los individuos capturados en la temporada no reproductiva fueron más brillantes que aquellos capturados en la temporada reproductiva. Este resultado podría deberse al programa de muda particular presente en Thraupidae, que incluye una única muda post-reproductiva completa. Si bien encontramos diferencias entre estaciones en la forma espectral en varias regiones corporales, no se detectaron diferencias en el tono, la intensidad del color de onda corta ni la intensidad del color de UV. Este es, de acuerdo a nuestro conocimiento, el primer estudio que muestra variación en la coloración del plumaje adulto de S. diadematus. Sugerimos que el dicromatismo en Thraupidae podría ser más común de lo que actualmente se piensa.

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