Invasive Species

An invasion has been underway that has continued to endanger much of Americas ecosystems. To call a species “non-native” or “invasive” does not sound too threatening, but the truth is they are one of the primary threats to native wildlife in an area. An invasive species can be any kind of living organism—an amphibian, mammal, plant, insect, fish, fungus, bacteria, or even an organism’s seeds or eggs—that is not native to an ecosystem and which causes harm to the environment, the economy or even, human health (Carroll).

Species have always been restless, continually testing their boundaries, but at the same time we have a global system that makes the transportation of plants and animals almost effortless on their part. One specific example

Their overly aggressive and territorial nature accounts for this. Pairs establish territories and defend them from other mute swans, birds, and mammals. Mute swans often cause the relocation of native birds from nesting and feeding areas. For example, they are responsible for driving the last remaining colony of black skimmers, a state-threatened species, from the Maryland portion of the Chesapeake Bay (Mute Swan…2003). Driving out a species is of less impact than high intensity interactions that can injure or even kill the “intruders”. Canada Goose goslings, for instance, have been injured or drowned by Mute Swans (Mute Swan: A Non-Native…2013). Movement of a species disrupts the ecological aspects of an area, but killing a species is very damaging to the biodiversity. Mute swans are also capable of inflicting great injury on humans and in a couple cases even death. In Des Plaines, a man drowned after being attacked by a mute swan. It was reported that the 37 year old was knocked out of his kayak while tending the birds (Nasaw and Geoghegan 2012). Anyone in and around the areas where the swans are nesting are in danger. As the population rises, these interactions with humans are only going to become more

Normally mute swans nest one time a year between the months of March and August. The nests are made next to water or on floating islands by the female. She uses building materials gathered by males, which includes grasses and twigs (Jimenez 2007). A pair often matches by the age of 2 even though they may not breed for another couple years. Although they pair, the swans usually do not mate for life; some have as many as four mates and even “divorce” one in favor of another (Ivory 2002). While in a nesting pair, both the male and the female play important roles. When the female lays the eggs, they both incubate, but the male usually only does while the female is away. The male spends most of his time guarding the nest. A normal clutch size has about 6 eggs, but the number can range from 5-10 (Reproduction: Let’s…2007). With a clutch that size, the swans can easily increase in population size over time as mute swans can mate every year after the age of 3. Mute swans have a relatively long life span of 20 to 30 years, but the reproductive rate considerably drops after the age of 20 (Mute Swan 2014). The long life span and high reproductive rate are unfavorable to the ecosystem and community the swans have