Health and Nutritional Status of a Perturbed Black-Necked Swan (Cygnus melanocoryphus) Population: Diet Quality

Abstract

The Cayumapu River's black-necked swan population in southern Chile lost its main dietary item, Egeria densa, during an environmental crisis which occurred in 2004 in the Carlos Andwanter Nature Sanctuary. The main goal of this study was to test the effect of diet on the physiologic response to this new ecologic challenge. The results revealed that the new diet of this population was composed primarily of roots and sedimentary microalgae, with chemical and energetic content similar to the diet of the control population. Nevertheless, the mean body mass of the Cayumapu River swans was 25% lower than that of control birds. In addition, the biochemical and hematologic profiles of the study population were indicative of malnutrition and a hyperferremic, hyperphosphatemic, and lymphopenic condition. Liver enzyme activities did not support that the malnutrition was a secondary consequence of liver dysfunction, as is expected under hemochromatosis or environmental toxics exposure.

The use of haemoglobin concentrations to assess physiological condition in birds: a review

“… Habitat quality and fragmentation (−) Amos et al (2013) Black-necked swan C. melanocoryphus ANS Ad. Habitats of varying food availability (−) Norambuena and Bozinovic (2009) Common tern S. hirundo CHA Pull. Social environment (colony size) − Minias et al (2015b) Gouldian finch E. gouldiae* PAS Pull.…”

Ecosystem processes, management and human dimension of tectonically-influenced wetlands along the coast of central and southern Chile

“…Research and development of conservation and monitoring strategies in the Rio Cruces wetland were strongly powered in 2004, when an environmental disaster threatened the conditions of the ecosystem. The conservation status of Black-necked swans was seriously endangered, when notorious environmental changes in the wetland were accompanied by emigration and mortality of swans and declining cover of the aquatic macrophyte plant Egeria densa, that used to be the primary food item of herbivorous water birds such as swans Norambuena & Bozinovic, 2009 ;Lagos et al 2008). Those environmental changes were recognized as a direct ISSN 0717-652X…”

Dietary habits of the black-necked swan Cygnus melancoryphus (Birds: Anatidae) and variability of the aquatic macrophyte cover in the Río Cruces wetland, southern Chile

“…maritima [13,58], and Lago Budi (ca. 38°S; southern Chile) where their main food is Stuckenia pectinata [59].…”