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

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.

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

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.

Response of Australian pied oystercatchersHaematopus longirostristo increasing abundance of the beach bivalve preyDonax deltoides

This study measured the response of Australian pied oystercatchersHaematopus longirostrison South Ballina Beach, New South Wales, Australia during a recovery in the stock of the primary prey speciesDonax deltoides, a large beach clam and commonly known as the ‘pipi’. It was predicted that oystercatcher counts would increase when pipi abundance increased (numerical response) and that oystercatcher feeding rates would also increase (functional response). Between Oct 2009 and Mar 2015, mean pipi density increased from c. zero to 30 pipis/m2. Mean oystercatcher feeding rates increased to an asymptote of c. 0.26 pipis/min. Breeding season mean counts of adult-plumage oystercatchers increased from 23 to 43, largely driven by non-territorial birds. Prey size selection was absent, both among different prey types and among pipis > 20 mm. This report provides some insights into the feeding ecology of oystercatchers on sandy ocean beaches that should be valuable in planning future studies.

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

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.

Count trends for migratory Bald Eagles reveal differences between two populations at a spring site along the Lake Ontario shoreline

The recovery of Bald Eagles (Haliaeetus leucophalus), after DDT and other organochlorine insecticides were banned in the United States, can be regarded as one of the most iconic success stories resulting from the Endangered Species Act. Interest remains high in the recovery and growth of the Bald Eagle population. Common to evaluating growth and recovery rates are counts at nesting sites and analyses of individuals fledged per season. But this is merely one snapshot that ignores survival rates as eagles grow to maturity. By analyzing indices from migration counts, we get a different snapshot better reflecting the survival of young birds. Different populations of Bald Eagles breed at different sites at different times of the year. Typical migration count analyses do not separate the populations. A separation of two distinct populations can be achieved at spring count sites by taking advantage of the tendency for northern summer breeding birds to migrate north in spring earlier than southern winter breeding birds who disperse north later in spring. In this paper I analyze migratory indices at a spring site along Lake Ontario. The analysis shows that eagles considered to be primarily of the northern summer breeding population showed an estimated growth rate of 5.3 ± 0.85% (SE) per year with 49% of eagles tallied in adult plumage, whereas the migrants considered to be primarily of the southern breeding population had an estimated growth rate of 14.0 ± 1.79% with only 22% in adult plumage. Together these results argue that the populations of southern breeding Bald Eagles are growing at a substantially higher rate than northern breeding eagles. These findings suggest that aggregate population indices for a species at migration counting sites can sometimes obscure important differences among separate populations at any given site and that separating counts by time period can be a useful way to check for differences among sub-populations.

Age-Based Plumage Changes in the Lance-Tailed Manakin: A Two-Year Delay in Plumage Maturation

I investigated the relationship of plumage to age and sex in the Lance-tailed Manakin (Pipridae, Chiroxiphia lanceolata) in the lowlands of western Panama from 1999–2004. I captured birds in mist nets, categorized their plumages, examined them for molt, and followed them for several years to document plumage changes. Male Lance-tailed Manakins exhibited three distinct postjuvenal plumages. Males achieved definitive adult plumage through sequential changes that occurred in the same order as in other Chiroxiphia manakins. Definitive male plumage developed over the same time span as reported for C. caudata but one year faster than C. linearis. Juvenal male plumage was similar to that of females, and 5% of 226 females had plumage similar to formative male plumage. Genetic sexing verified that changes observed late in the formative male plumage unambiguously identified sex and age of individual birds. This information can be used in behavioral studies to identify the age of male Lance-tailed Manakins captured in any of the predefinitive plumage stages.

Cryptic Dichromatism and Seasonal Color Variation in the Diademed Tanager

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.

The Problem of Molt and Plumage Homologies and the First Plumage Cycle

The recent paper by Howell et al. (2003) recognizes that birds have evolved special plumages before entering the adult plumage cycle that should, therefore, be named differently in the terminology introduced by Humphrey and Parkes (1959) for plumages and molts (the H-P system). We agree with the principle of this suggestion, but we nevertheless suggest that birds take different lengths of time and different numbers of molts to enter the adult molt cycle and to acquire the adult plumage. We suggest that this variation should not be concealed by the assumption of an artificial first cycle of the same length as subsequent cycles, but should be reflected in the terminology of plumages and molts. We also suggest a distinction between entering the adult molt cycle and entering the adult plumage cycle. A main problem of the H-P system and Howell et al.'s modification is the claim that it is based on the concept of homology. In our opinion, there are no firm and convincing criteria on which to base a plausible phylogeny of plumages and molts. We would prefer to call Howell et al.'s modified H-P system a “terminology” for molts and plumages without the claim to determine homologies. We suggest that plumages or molts having the same Howell et al. term should be called “comparable,” rather than homologous. Moreover, it is debatable whether the phylogeny of molt is always the same as the phylogeny of plumages, as the H-P system claims by linking one molt to one plumage. We believe that the H-P system and Howell et al.'s modification of it remains too rigid to adequately reflect the evolution of molts and plumages. El Problema de las Homologías de la Muda y el Plumaje y el Primer Ciclo del Plumaje Resumen. El artículo reciente de Howell et al. (2003) reconoce que las aves han desarrollado a través de la evolución plumajes especiales que ocurren antes del ciclo del plumaje adulto y que deberían, por lo tanto, tener un nombre diferente en la terminología introducida por Humphrey y Parkes (1959) para los plumajes y las mudas (el sistema H-P). Nosotros estamos de acuerdo con el principio de esta sugerencia, pero sin embargo sugerimos que las aves toman diferentes períodos de tiempo y diferentes números de mudas para entrar al ciclo de muda adulto y para adquirir el plumaje adulto. Sugerimos que esta variación no debería ser enmascarada por la suposición de un primer ciclo artificial de la misma longitud de los ciclos subsecuentes, sino que debería reflejarse en la terminología de plumajes y mudas. También sugerimos una distinción entre entrar al ciclo de muda adulto y entrar al ciclo de plumaje adulto. Un problema principal del sistema H-P y de la modificación de Howell et al. es la idea de que están basados en el concepto de homología. Nuestra opinión es que no existen criterios firmes y convincentes sobre los cuales basar una filogenia plausible de los plumajes y las mudas. Preferiríamos tratar al sistema H-P modificado por Howell et al. como una “terminología” para mudas y plumajes, sin pretender determinar homologías. Sugerimos que los plumajes o las mudas que tienen el mismo término en el sistema de Howell et al. deberían llamarse “comparables” en lugar de homólogos. Más aún, es debatible si la filogenia de la muda es siempre igual a la filogenia de los plumajes, como el sistema H-P asevera al conectar una muda con un plumaje. Creemos que el sistema H-P y la modificación de Howell et al. son todavía demasiado rígidos para reflejar adecuadamente la evolución de la muda y los plumajes.