Päiväkirja-arkisto kohteelle marraskuu 2021

25. marraskuuta 2021

The European Starling (Sturnus vulgaris)

The European Starling (Sturnus vulgaris) is an invasive species that is native to Europe. It was intentionally introduced in 1890 to New York City’s Central Park by the America Acclimatization Society. They released 100 birds to Central Park with the hopes of introducing the many bird species that were mentioned throughout Shakespeare’s works and seeing them represented in North America [1].

Since their introduction, the European Starling has become widespread across North America, ranging from Mexico all the way up to the Northern treeline in Canada. Already by 1950 they had spread across the North American continent and reach the Pacific Coast. They prefer open regions such as fields, pastures, lawns, marshes, and shorelines, and so, they can be found in both rural and urban settings.

Starlings are aggressive cavity nesters who live in enormous flocks, outcompeting native cavity nesting birds for nest sites. Starlings typically build nests in tree holes, nest boxes, openings in building walls, cliff crevices and rural mailboxes. They often form roosts under bridges, on ledges, or in trees. The combined weight of the birds has been known to break branches of trees. As a stewardship action to reduce this invasive alien species impact, you can repair and seal and exterior cavities where birds can nest, with openings like vents that can’t be sealed the openings should be covered with wire mesh.

European Starlings have short stubby tails and triangular wings. They are generally described as “chunky” and humpbacked birds. As adults they range 19-23cm in length with a wingspan of 31-44cm. Breeding starlings have glossy black plumage with purple and green reflections, yellow ills, and reddish brown legs. In the Fall, Starling’s bills become darker in colour and white spots develop on the body feathers.

European starlings are omnivores, feeding mainly on insects and fruit, but will also forage on human food waste and on agricultural crops [1]. For this reason, as another stewardship action, you can eliminate anthropogenic food sources which includes bird feeders for other species.

A fun fact about European Starlings is that they are excellent vocal mimics and can mimic the song of up to 20 different bird species.

  1. New York Invasive Species (IS) Information. European Starling. Updated: May 31, 2021 [accessed September 10, 2021]. Retrieved from: http://nyis.info/invasive_species/european-starling/
Lähetetty 25. marraskuuta 2021 17:45 käyttäjältä jgilice1 jgilice1 | 0 kommenttia | Jätä kommentti

30. marraskuuta 2021

European Green Crab (Carcinus maenas)

The Green Crab is a small shore crab found in shallow water, generally in sheltered areas. They appeared in the 1950s in the bay of Fundy, probably after moving up the infested coast of northeastern united states. They are common in salt marshes, on sandy beaches, and on rocky coasts, and they can tolerate a wide range of salinities. In adult green crabs their carapace can reach up to 10cm but are usually less than 8cm. They range from mottled, green, red, yellow, to brown in coloration. They have serrated shells with five spines on either side of the eyes and three between the eyes. Their back legs are pointed, slightly flattened, and hairy.

Green crabs are voracious consumers of both plants and animals, especially soft-shelled clams, oysters, quahogs, and mussels. They destroy beds of bivalves and uproot Eel grass, an important habitat-forming species for native fish, invertebrates, and waterfowl. They also outcompete native crab species for resources such as food and space. These behaviours all result in a negative impact on biodiversity and harm local fisheries. They have been given the nickname cockroaches of the sea.

Green Crabs are thought to spread mostly during their larval stage where they are moved about in ballast water transfers or drifting on ocean currents. Their larval stage can last up to 90 days. Adult Green Crabs can survive for a long time in fresh water and out of the water. They can also be introduced if fishing gear is moved to a new area or if crabs are intentionally discarded with bycatch outside of their catch area.

Always remember to clean, drain, dry your boat before entering a new body of water to prevent the spread of green crabs. If Green Crabs are caught as by-catch do not release them.

Lähetetty 30. marraskuuta 2021 19:30 käyttäjältä jgilice1 jgilice1 | 0 kommenttia | Jätä kommentti