Cecilia P. Calabuig

Settlement and Successful Breeding of Reintroduced Spanish Imperial Eagles Aquila adalberti in the Province of Cadiz (Spain)

Summary. A project to reintroduce the Spanish imperial eagle in the province of Cadiz (Andalusia, Spain) began in 2002. The aim was to restore the former breeding nucleus, to encourage subpopulation interconnection and to ensure the long-term persistence of the southern metapopulation of this endemic Iberian species. A population reinforcement programme also began in 2005 at a location in the Doñana area (Andalusia, Spain) to improve the viability of this endangered subpopulation. Between 2002 and 2010, a total of 73 young Spanish imperial eagles were released at four locations by means of hacking. As a result, in 2010 a released male bred successfully with a non-reintroduced female and two young were reared. This was the first successful breeding event recorded in Cadiz province since 1960. An additional territorial pair also settled in the release area in 2010 and four more translocated individuals have made breeding attempts within nearby breeding subpopulations since 2006. The settlement and breeding of reintroduced individuals is the starting point of a future population and constitutes a relevant indicator for the evaluation of the project.

Sexual size dimorphism and sex determination by morphometric measurements in the Coscoroba Swan

The accuracy of morphological sexing and the occurrence of sexual dimorphism were analyzed in mature and immature Coscoroba Swans (Coscoroba coscoroba, Anatidae) near the Estação Ecológica do Taim, southern Brazil. On the basis of weight and 10 linear measurements of external morphology, multivariate analysis of variance showed that males were consistently larger than females (sex confirmed via genetic markers) and mature birds were consistently larger than immatures. Overall, 38% of immatures and 14% of mature birds were sexed incorrectly by cloacal examination when compared to genetic data. Therefore, we performed a discriminant function analysis of different age classes based on morphometric measurements. Mature birds were sexed with 96% accuracy using head and tarsus lengths as predictor variables, whereas immatures were sexed with 90% accuracy based on head and forearm lengths. Method validation conducted with data for additional mature sampled in a different year showed that the use of head length alone was as accurate for sexing (92% correct classification) than discriminant functions based on two characteristics (91%).

Factors affecting plasma biochemistry parameters and physical condition of Osprey ( Pandion haliaetus ) nestlings

AbstractWe assessed the normal values for 15 blood plasma biochemistry parameters and three indices of body condition (IBCs) in free-living Osprey (Pandion haliaetus) nestlings in Brandenburg (Germany). Values were compared with those of other raptors, and possible sexual and age-related differences were examined. In addition, we looked for possible relationships of habitat quality (measured in terms of foraging conditions and human disturbances) to nestling nutritional condition and productivity. Female nestlings showed higher mean urea levels and lower glucose values than males, which could be related to higher growth rates and nutrient demand of females at the end of the nestling period. Seven parameters also showed variation with age, probably relating to increasing body mass, metabolic rates, and physical activity during the pre-fledging stage. Conversely, the IBCs showed poor correlations with selected nutritional parameters, probably due to the homogeneously acceptable nutritional conditions of the nestlings. Finally, we found that Ospreys did not seem to adjust initial parental investment in relation to habitat quality, since productivity was not affected by habitat indicators. However, in large broods, but not in small ones, nestling nutritional condition improved as foraging conditions improved. These results suggest that females that are in better physical condition seem to produce more and better nourished nestlings in better foraging conditions.ZusammenfassungEinflussfaktoren auf biochemische Blutplasma-Parameter und körperliche Kondition nestjunger Fischadler (Pandion haliaetus) Wir beurteilten Normalwerte für 15 biochemische Blutplasma-Parameter und drei Indizes für die Körperkondition (Indices of Body Condition—IBCs) bei freilebenden nestjungen Fischadlern (Pandion haliaetus) in Brandenburg (Deutschland). Die Werte wurden mit denen anderer Greifvogelarten verglichen und mögliche geschlechts- und altersabhängige Unterschiede wurden untersucht. Zusätzlich haben wir denkbare Zusammenhänge zwischen der Habitatqualität—gemessen anhand der Lage von Gebieten der Nahrungssuche und anhand menschlicher Störung—und dem Ernährungszustand der Nestlinge sowie der Reproduktion untersucht. Weibliche Nestlinge zeigten höhere Harnstoff-Durchschnittswerte und geringere Glukose-Werte als männliche, was mit einer höheren Wachstumsrate und einem höheren Nährstoffbedarf bei den jungen Weibchen gegen Ende der Nestlingsperiode zusammenhängen kann. Sieben Parameter zeigten Veränderungen abhängig vom Alter, wahrscheinlich im Zusammenhang mit der zunehmenden Körpermasse, mit dem höheren Metabolismus und mit der steigenden körperlichen Aktivität während der Phase kurz vor dem Flüggewerden. Umgekehrt zeigten die IBCs geringe Korrelationen mit ausgewählten Parametern bezüglich der Nährstoffversorgung, wahrscheinlich aufgrund angemessener und gleichmäßiger Versorgung der Nestlinge. Schließlich fanden wir, dass Fischadler ihre ursprünglichen elterlichen Investitionen vermutlich nicht der Habitatqualität anpassten, da die Reproduktion nicht von den Habitateigenschaften beeinflusst wurde. Jedoch verbesserte sich die Nährstoffversorgung in großen Bruten mit besseren Bedingungen zur Nahrungssuche, nicht aber in kleinen Bruten. Unsere Ergebnisse legen es nahe, dass Weibchen mit besserer Körperkondition mehr und besser ernährte Jungvögel hervorbringen, insbesondere unter besseren Bedingungen für die Nahrungssuche.

Plasma alkaline phosphatase as a sensitive indicator of age and skeletal development in wild coscoroba swans

Context. Recent studies have suggested that plasma alkaline phosphatase (ALP) can be used to assess skeletal development as well as health status in wild animals. Aims. However, the information about age-related dynamics of ALP in birds, especially in precocial species, is very scarce. Therefore, before ALP measurements can be effectively interpreted, it is necessary to determine its normal variation for each species, age group and sex. Methods. Here, we report total-ALP levels of free-living coscoroba swans (Coscoroba coscoroba) from the most important breeding and moulting population in Brazil. Data were gathered during the moulting period and categorised according to sex and the following three different age classes: chick (n = 11), young (n = 14) and mature (n = 29). Key results. ALP levels were related to the longitudinal measure of the bones, gradually diminishing with age and showing significant differences among birds of different age classes. In all age groups, no effect of sex on T-ALP concentration was detected. Conclusions. We conclude that measuring ALP facilitates the discrimination among different-aged individuals with similar plumage characteristics and body size.

Blood Chemistry of Wild Brazilian Coscoroba Swans during Molt

The Coscoroba Swan (Coscoroba coscoroba) is an unusual member of the Anatidae found in South America, from the Falkland Islands and Tierra del Fuego through Chile and Argentina, Uruguay, and Paraguay as far north as Mato Grosso do Sul in Brazil. The species is not threatened globally, but some local populations have declined and the status of others is unknown. The objective of this study was to quantify the plasma chemistry of a wild population of Coscoroba Swans in southern Brazil during their molting period. We captured 12 chicks, 14 juveniles, and 31 mature birds. The following blood parameters were measured: glucose, cholesterol, triglycerides, HDL cholesterol, uric acid, creatin-kinase, aspartate amino transferase, alanine-aminotransferase, alkaline phosphatase, amylase, and pancreatic amylase. Significant differences between males and females were not observed for any of the parameters, and only the levels of alkaline phosphatase differed significantly among age groups.

Morphometric sex determination of young Ospreys Pandion haliaetus using discriminant analysis

Capsule Discriminant functions based on morphometric variables provide a reliable method for sex identification of free‐living and hacked young Ospreys. Aims To describe an easy, accurate and low‐cost method for sex determination of fully grown nestling and fledgling Ospreys Pandion haliaetus based on morphometric measurements. Methods Four different measurements were taken in 114 birds (40–73 days old) and a DNA analysis, using PCR amplification, was carried out for sex identification. A forward stepwise discriminant analysis was performed to build the best explanatory discriminant models, which were subsequently validated using statistics and external samples. Results Our best discriminant function retained forearm and tarsus as the best predictor variables and classified 95.1% of the sample correctly, supported also by external cross‐validations with both hacked and free‐living birds. Moreover, a discriminant function with only forearm as predictor showed a similar high correct classification power (93.4%). Conclusions These discriminant functions can be used as a reliable and immediate method for sex determination of young Ospreys since they showed high discriminant accuracy, close to that of molecular procedures, and were supported by external cross‐validations, both for free‐living and hacked birds. Thus, these morphometric measurements should be considered as standard tools for future scientific studies and management of Osprey populations

Allometry as evidence of sexual selection in monochromatic birds: the case of the Coscoroba Swan (Anseriformes: Anatidae)

The Coscoroba Swan, Coscoroba coscoroba (Molina, 1782), is a poorly known aberrant Anserine endemic to South America. We captured adult birds (189 male, 157 female) from the largest population in Brazil at the Taim Ecological Reserve, State of Rio Grande do Sul, Brazil. Different patterns between sexes can reflect differences in selection, and positive allometry may indicate that a character is sexually selected. We used body weight and 10 morphological measurements to examine allometric differences between males and females of C. coscoroba. Males were consistently larger than females. Analysis of scaling relationships against body mass showed that nostril, tail, wing and bill height were positively allometric (i.e., heavier birds had relatively larger character lengths), but there were no sexual differences in allometric slopes. However, for a given mass, mature females had longer tails, longer wings (up to metacarpophalangeal articulation) and shorter heads than males. In the light of current debate in the literature, we discuss whether such positively allometric traits and sexual differences in scaling may be indicative of sexual selection. Although Coscoroba Swan is a monogamous species, increasing the size of some attributes may confer some advantage for mate selection or male-male competition and, contrary to other studies, we suggest that positively allometric slopes alone should not be considered as evidence for sexual selection of the considered traits.