Tag Archives: invasive

Mallards (Anas platyrhynchos)

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Mallard ducks tolerate humans… maybe a little too well.

Mallard ducks are the most abundant and widespread waterfowl in the Northern Hemisphere. They are found from Arctic tundra to subtropical regions on every continent.

Mallard female and male (green head). Photo ODFW.

In Oregon, Mallards are found near coastal and inland marshes, fresh or salt water wetlands and estuaries; lakes, ponds, and rivers; and golf courses and agriculture fields. They are particularly attracted to shallow water with aquatic vegetation.

Flexible Omnivore

Mallards are flexible omnivorous eaters and will vary their diet based on breeding cycle, availability, and migration. As a general rule they primarily eat, or dabble, plant materials. They will also dabble gastropods (slugs, snails, etc.), invertebrates (flies, beetles), crustaceans (crab, shrimp, barnacles, etc.), worms, and frogs. They have also been observed hunting as a flock other small birds and larger animals.

Oregon Department of Fish and Wildlife urge people to not feed geese and ducks. Feeding can create a concentration problem and invites disease outbreaks.

One Eye Open

Not only will they eat many different animals, but many different animals will eat them. Predators could include raptors (like eagles, falcons, harriers, owls, etc.), mammals (such as snakes, raccoons, skunks, cats, dogs, etc.) and others who target eggs and nestlings.

The ability to sleep with one eye open was first demonstrated in mallards, but is not believed to be widespread among birds. This ability allows one brain hemisphere to sleep, while the other is aware.

And Humans…

Ducks were domesticated at least 4,000 years ago in many areas for their meat and eggs. Pure bred Mallards are sometimes domesticated today for their meat and eggs. 

Almost all domestic duck breeds can be traced back to Mallards. Domestic ducks and Mallards are the same species, with some of the same genes. Mallards have the ability to cross breed with 63 other duck species and create fertile hybrid offspring. This ability can dilute a duck breed population and cause severe ‘genetic pollution’ leading to the extinction of wild, indigenous waterfowl. They are considered an invasive species in some areas.  

Mallards are the most common variety of ducks hunted for sport due to high population volumes. They are also considered to be quite tasty. Be sure to check with local regulations before hunting or taking any bird.

Caution

Mallards can become aggressive during the breeding season as they compete and work out territorial disputes. Aggressive behavior can include charging and chases, ripping out feathers and skin, and noise making. Males are generally more aggressive and will repeatedly attack each other. Domestic ducks are significantly less aggressive than mallards.

STATS: Color: breeding males have a solid, dark green head, reddish-brown breast, and pale body; males and females have bright blue patch on trailing edge of wings. Size will vary: overall length, 147 cm (23 inches); wingspan, 89 cm (35 inches). May migrate. Feathers: Special oils let feathers easily shed water. Mallards are adapted for swimming and floating, and some are even talented divers.

REFERENCES
–Oregon Dept. of Fish and Wildlife pages: Swans, Ducks, and Geese (https://myodfw.com/wildlife-viewing/species/swans-ducks-and-geese) and Game Birds, Mallard (https://myodfw.com/game-bird-hunting/species/mallard, and pamphlet Living with Birds (https://www.dfw.state.or.us/wildlife/living_with/birds.asp)
–Wikipedia, Mallard (https://en.wikipedia.org/wiki/Mallard)

Tree Lupine (Lupinus arboreus)

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Public domain, Wikimedia Commons

What’s that soft yellow bush in the distance? It just might be a Tree Lupine (Lupinus arboreus). The common names are yellow bush lupine (US) or tree lupin (UK).

This perennial will grow to about 79-inches in full sun. Tree lupins typically live up to seven years and are hardy to 10˚F.

The attractive yellow flowers held on a 12-inch stem is rich in nectar and pollen. The gray-green leaves are palm-shaped and covered with fine, silky hair.

Lupins are attractive to many bees, butterflies, and moths. Tree Lupins host to ten or more butterflies and moths. Some have estimated the number to be upwards of 39 in total. Lupines do not appear to be attractive to birds.

Wolf?

The term lupine is from the Latin for “wolf,” referring to the mistaken belief that these plants deplete soil minerals. The opposite is actually true.

Many species of Lupine will collect nitrogen from the air. This ability gradually enriches surrounding soils and may displace native varieties adapted to more nitrogen-poor conditions.

Invasive Tendencies

Tree lupins are strong growers and can outcompete other grasses, forbs, and native plants. It grows in a number of different soils with good drainage including sand dunes and coastal sage scrub. At one time, this plant was used to stabilize sand dunes and other soils along the Oregon and California coast.

This species can threaten native plants through hybridization. There are approximately 220 species of lupines with many growing in the North American west.

Yellow Lupin creates a lot of seeds every year. These seeds persist in the soil for a very long time and can create a seed bank.

Unsprouted seeds collect and lay dormant in a shallow mat below the shrub. This seed bank will sprout with even minimal disturbance. Disturbances can include manmade or environmental. Even something like rodent activity or wind is enough to cause sprouting.

Lupins can be toxic depending on season, variety, and plant parts. Seeds for instance are often very toxic. A wide variety of less invasive and colorful lupines are available commercially.

REFERENCES:
–Tree Lupine, https://www.fws.gov/refuge/Humboldt_Bay/wildlife_and_habitat/YellowBushLupine.html
–Lupine, https://www.britannica.com/plant/lupine
—Lupine arboreus, https://calscape.org/Lupinus-arboreus-()