Comparison of Two Different Feather Sampling Methods to Measure Corticosterone in Wild Greater Flamingos (Phoenicopterus roseus) and Wild Mallards (Anas platyrhynchos)

This research project had the aim to validate the possible alternative and less-painful sampling method of cutting feathers close to the skin instead of plucking them for subsequent feather corticosterone analysis, confirming recently-published results for other species in captivity. Analyzing CORTf is often used in animal welfare studies in combination with behavioral monitoring. The background of this idea was to act in the sense of animal welfare and reduce the burden of animal studies according to the 3-R-Principle (Replacement, Reduction, and Refinement) by refining procedures. To confirm the hypothesis that the sampling method itself has no influence on CORTf levels measured, plucked and cut samples of the respective bird were collected. Birds of two wild species were used: the Mallard (Anas platyrhynchos) and the Greater Flamingo (Phoenicopterus roseus). The CORTf was measured by using an enzyme-linked immunosorbent assay (ELISA). The determined values were inspected for their mean values, standard deviation (SD), and average differences. Afterwards, the CORTf levels of both species were compared, according to the sampling method, with the concordance correlation coefficient (CCC). In the Bland-Altman (BA) plot the differences of the methods were displayed against the mean values. Additionally, sex, as a possible factor influencing CORTf, was analyzed using the Mann-Whitney U test. The values of CCC showed poor agreement in the comparability of the two methods, whereas the concordance of the BA plot was decent. The average differences between the methods were marginal for both species (Mallards: −0.16 pg/mm, Flamingos −0.13 pg/mm). In summary, all anomalies or differences between the methods were negligible. Therefore, the alternative sampling method seems to be as suitable as the common standard method. No significant difference was found between females and males. Nevertheless, our results suggest that CORTf should not be interpreted in just considering the values themselves, but the results they should be analyzed in the context of a wider set of parameters. Hence, further studies are encouraged to create a larger data pool.

Population and conservation threats to the Greater Flamingos Phoenicopterus roseus (Aves: Phoenicopteriformes: Phoenicopteridae) at Basai Wetland and Najafgarh Jheel Bird Sanctuary, Haryana, India

Greater Flamingos are the largest and most widespread, among other species of Phoenicopteridae. This study documents the population structure and conservation threats affecting the population and habitat of the flamingos at Najafgarh Jheel Bird Sanctuary and Basai wetland in Haryana, India. The study areas were surveyed monthly between May 2019 to February 2020 at regular intervals. A Nikon 8 X 40 field binoculars and a Nikon SX60 camera were used to observe flocks of P. roseus. A total of 65 flocks of flamingo were observed, and 6,768 individuals were counted using point counts method. Najafgarh Jheel Bird Sanctuary holds a major proportion of their population comprising about 91.78 % and Basai wetland holds about 8.21 % of their population, while 52.46 % of the total population were classified as adults, and 47.53 % were juveniles (sub-adults). Habitat fragmentation resulting from construction of roads is one of the major threats, while overgrowth of water hyacinth, cattle grazing and fishing activities at Basai Wetland, adversely affected the flamingos. At the Najafgarh Jheel, cattle grazing was considered to be the major threat, followed by the overgrown water hyacinth, fishing activities and collision with high tension power lines.

Feather Corticosterone Measurements of Greater Flamingos Living under Different Forms of Flight Restraint

Deflighting zoo birds is a practice that receives increasing criticism due to its presumed incompatibility with animal welfare. To our knowledge, this is the first approach to address this problem in a scientific way. To do this, we compared feather corticosterone (CORTf) from Greater Flamingos (Phoenicopterus roseus, n = 151) of different flight status (i.e., pinioned, feather clipped, airworthy) from twelve different zoological institutions. To complement the hormone measurements, behavioral observations (scan samplings) were conducted prior to feather sampling within the presumed time frame of feather growth. We hypothesized that CORTf of the deflighted flamingos would differ from CORTf of their airworthy conspecifics. No significant difference in CORTf was found between the three groups, and our hypothesis was rejected. However, the impact of the institution itself (i.e., the housing conditions) proved to be the most dominant variable (variance between the institutions = 53.82%). Due to high variability, the behavioral observations were evaluated descriptively but did not give rise to doubt the findings in CORTf. Therefore, we assume that the method of flight restraint of Greater Flamingos does not have a measurable effect on CORTf. We consider this model for evaluating animal welfare of zoo birds a useful tool and provide ideas for further adjustments for consecutive studies.