Glaucous winged gull
|Glaucous Winged Gull|
Glaucuos winged gull (Larus glaucescens) is a bird common to the northwest coast of North America. Although there have been recent sightings in more tropical areas. The bird can be identified by its upper body being a darkish grey hue while the belly is white. The wings are also a dark grey and the beak is yellow with a red spot on the lower half of the beak. Young birds tend to be brown with darker beaks and eventually grown in to the white and gray see in adults. They have an average wing span of 130 cm.
Glaucuos winged gull tends to nest in northern areas with high vegetation. Studies conducted in Greys Harbor, Washington showed that places with dense vegetation were favored as nesting spots. Thick foliage protects eggs from predators and creates a stable base for the nest. Places like these showed better success rate for the gulls. In cities they can be found nesting on flat roofs and in proximity to a food source.
Many different types of seagulls are considered to be pests all around the world. The Glaucous winged gull is no exception. Studies have found that the loafing of these gulls is dependent on environmental factors. An abundance of food can lead to so called loafing as well as height of tide and time of day. A negative factor of loafing is that it can help spread disease and slowly erode buildings due to the accumulation of droppings.
In big cities it is common to find gulls who would eat pretty much anything including chicks. However in the wild it has been found that feeding habits depend largely on breeding habits. Non breeding gulls were seen to favor a type of fly larvae (Fucomyia frigida) who live in decaying brown algae. Their foraging strategy was to maintain a permanent residence near the food source (loafing). The amount of gulls is directly proportional to the amount of food present during that time. Breeding gulls tend to favor fish and food from animal farms. They are capable of eating rabbits and pigeons.
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Henson, Shandelle M., James L. Hayward, Christina M. Burden, Clara J. Logan, and Joseph G. Galusha. "Predicting Dynamics Of Aggregate Loafing Behavior In Glaucous-Winged Gulls (Larus Glaucescens) At A Washington Colony." The Auk 121.2 (2004): 380. Print.
Philips, Karl W., Smurti P. Damania, James L. Hayward, Shandelle M. Henson, and Clara J. Logan. "Habitat Patch Occupancy Dynamics of Glaucous-winged Gulls (Larus Glaucescens) II: A Continuous-time Model." Natural Resource Modeling 18.4 (2005): 441-68. Print.
Verbeek, N. A. M. 1993. Glaucous-winged Gull (Larus glaucescens). In The Birds of North America, No. 59 (A. Poole, and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists' Union, Washington, D.C.
White, Aija F., Joel P. Heath, and Brian Gisborne. "Seasonal Timing of Bald Eagle Attendance and Influence on Activity Budgets of Glaucous-winged Gulls in Barkley Sound, British Columbia." Waterbirds 29.4 (2006): 497-500. Print.