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

Abstract

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.

Validation of an Alternative Feather Sampling Method to Measure Corticosterone

“…To assess the relevance of the within-individual variation (median 15.6% for Anser, 17.8% for Anas), this and the maximum values (6.99 pg/mm in Anser, 4.28 pg/mm in Anas) must be compared to values from animals kept under different husbandry conditions. Since there are no values from stressed Anser and stressed Anas available in the literature, we discuss results of a study performed on Greater Flamingos for an estimation [48]. Stress was expected in one group due to repeated attacks by cranes.…”

“…Concerning this topic, ongoing studies, as well as currently published studies, focus on the evaluation of deflighting zoo birds, the comparison between different husbandries and the welfare implications. These deal with the species Greater Flamingo (Phoenicopterus roseus) [48] and Great White Pelican (Pelecanus onocrotalus) (ongoing study). The planning, structure and realization of research projects compared to these could also be expanded and simplified with this non-invasive sampling method.…”

“…To create a conclusive study for the comparison of plucked and cut feathers, there is the need to use a trial group with preferably similar characteristics [46][47][48]. In the chosen groups of ducks and geese, the individuals of each species were of the same age.…”

The Sustainability of Keeping Birds as Pets: Should Any Be Kept?

“…This can be done either to prevent the bird from flying away and escaping or, in an attempt to keep the bird safe, as the home where they live is dangerous for free-flying birds. However, wing-clipping should be avoided, except in rare situations where it improves bird welfare, and the process needs to be carried out correctly with the trim being functional and appropriate to the species of bird [ 39 ]. For example, asymmetric trimming can lead to major welfare problems.…”

Research Note: A sip of stress. Effects of corticosterone supplementation in drinking water on feather corticosterone concentrations in layer pullets

“…The measurement of feather corticosterone concentration ( fCORT ) is a comparatively new and increasingly used method in stress research in wild and captive birds as well as in poultry ( Carbajal et al, 2014 ; Romero and Fairhurst, 2016 ; Häffelin et al, 2020 ; Leishman et al, 2020 ; Monclús et al, 2020 ; Reese et al, 2020 ). Numerous studies have reported a stable incorporation of corticosterone in feathers and a positive correlation between corticosterone concentrations in feathers and in peripheral blood ( Bortolotti et al, 2008 ; Romero and Fairhurst, 2016 ).…”