Ecología y etología de la depredación de dos especies de aves acuáticas en un ambiente salino extremo

Content Provider	Semantic Scholar
Author	Gallegos, Peralta César, Julio
Copyright Year	2007
Abstract	Solar saltworks are complex hypersaline ecosystems, where diverse species which constitute the biotic communities have ecological characteristics which allow them to take advantage of the food resources as well as the available physical and chemical elements to survive. So, species of aquatic birds that inhabit those ecosystems have had to develop predation and behavior strategies that allow them to exploit the alternative or available food resources. On this context, this work, carried out from december 2002 to June 2003, focused on knowing aspects of the ecology and ethology of two aquatic bird species: the Western Gull (Larus occidentalis) and the Eared Grebe (Podiceps nigricollis) which inhabit the Guerrero Negro, B.C.S., solar saltworks whose territorial extension is 33,000 hectares. In this work it is documented findings related to the learning of these two bird species, from which they develop predatory and feeding behaviors for exploitation of particular resources of the Guerrero Negro solar salworks. So, it is described the typical hunting pattern by which the Western Gull captures and consumes the Eared Grebe, and the factors that influence the behavior and predatory efficiency. The predatory efficiency of predation of the Western Gull on the Eared Grebe was too high, because all the hunting actions were successful. It is also documented the typical foraging pattern of the Western Gull on the brine fly larvae Ephydra sp., another of the available alternative food resources in the solar saltworks. The Western Gulls can feed on living larvae of this brine fly, being this larvae their one and only food, and constitute by consecuence the total content mass in their proventricoulus and stomach. The availability of this resource is practically unlimited regarding the biomass, although it is restricted to specific zones in the solar saltworks, iwhere salinity enhance its massive production. On the other hand, regarding the Eared Grebe (a species that winters in the solar saltworks from December to June) it was determined that it uses three types of invertebrates as part of its diet: Artemia salina, Ephydra sp. (adult, larvae and pupae) and Tricocorixa sp. existing in the solar saltworks. It was evaluated the contribution of these components of the diet in the weight gain of the Eared Grebes prior to their departure to their breeding grounds. Females get a weight gain of 158.34 g, and males 176.2 g in average. It was also determined their main foraging areas in the solar saltworks, where it was observed that to a higher prey density correspond higher numbers of Eared Grebes. The extremely high salinity of the ponds which constitute the solar saltworks, results in a limited environment for the presence of many living organisms. Regardless, some bird species as the Western Gull and the Eared Grebe, as it is first documented by this work, have developed behaviors, hunting and selection of particular or alternative food resources strategies, which allow and enhance their surviving in a hypersaline environment.
File Format	PDF HTM / HTML
Alternate Webpage(s)	http://dspace.cibnor.mx:8080/bitstream/handle/123456789/172/peralta_j.pdf?isAllowed=y&sequence=1
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article