Silver Gulls Research Paper
OPTIMAL FORAGING PATTERNS IN SILVER GULLS (LARUS NOVAEHOLLANDIAE)
ABSTRACT
There appears to be different types of foraging behaviour patterns that are shown by different species throughout the world. These different patterns affect the amount of food gained by the individual as well as the amount of food gained by others in that species. In this study the silver gull’s (Larus novaehollandiae) forging patterns were studied, to determine what, if any, foraging strategies they engaged in. Three alternative hypothesis were tested, the first being that the gulls would forage where the food was at its highest density. The second was the gulls ignore, or cannot assess, patch quality, and finally the gulls forage in such a way as to maximise their own rate of food intake. It was found that the gulls split themselves into groups relative to the density of the food in each patch so that the ratio of food in the patch matched the ratio of gulls foraging. The first hypothesis was accepted while the second and …show more content…
novaehollandiae, as it is at almost any watered habitat throughout Australia, New Zealand and New Caledonia, although never far from land. L. novaehollandiae has become a very successful scavenger and regularly feasts on human refuse. This assists in the study of these birds as they are well accustomed to being fed by humans.
In the mid-1960’s the optimal foraging theory was introduced (Kennedy & Gray, 1993), which was based on assumptions that were gathered from the diet, patch choice and movement of the chosen species (Pyke, 1984). This theory evolved into the theory of ‘Ideal Free Distribution’ whereby the distribution of organisms between resource sites should match distribution of the resources (Kennedy & Gray, 1993), this is based on an ideal free model that predicts the ideal distribution when individuals in a habitat are free to move between patches (Sutherland & Parker,
ABSTRACT
There appears to be different types of foraging behaviour patterns that are shown by different species throughout the world. These different patterns affect the amount of food gained by the individual as well as the amount of food gained by others in that species. In this study the silver gull’s (Larus novaehollandiae) forging patterns were studied, to determine what, if any, foraging strategies they engaged in. Three alternative hypothesis were tested, the first being that the gulls would forage where the food was at its highest density. The second was the gulls ignore, or cannot assess, patch quality, and finally the gulls forage in such a way as to maximise their own rate of food intake. It was found that the gulls split themselves into groups relative to the density of the food in each patch so that the ratio of food in the patch matched the ratio of gulls foraging. The first hypothesis was accepted while the second and …show more content…
novaehollandiae, as it is at almost any watered habitat throughout Australia, New Zealand and New Caledonia, although never far from land. L. novaehollandiae has become a very successful scavenger and regularly feasts on human refuse. This assists in the study of these birds as they are well accustomed to being fed by humans.
In the mid-1960’s the optimal foraging theory was introduced (Kennedy & Gray, 1993), which was based on assumptions that were gathered from the diet, patch choice and movement of the chosen species (Pyke, 1984). This theory evolved into the theory of ‘Ideal Free Distribution’ whereby the distribution of organisms between resource sites should match distribution of the resources (Kennedy & Gray, 1993), this is based on an ideal free model that predicts the ideal distribution when individuals in a habitat are free to move between patches (Sutherland & Parker,