Category Archives: Wildlife

Interpretive Blogs about Wildlife and Plants

American dipper (Cinclus mexicanus)

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The American dipper appears as a small nondescript bird found along the west coast from Panama to Alaska. Take another look. Sometimes big surprises come in little packages.

American dipper

What makes this species special? Why is this nondescript, dark brown to gray bird amazing? It doesn’t look amazing, but don’t judge too quickly… several things make them very special.

Indicator Species

Think of the old reference to a ‘Canary in a Gold Mine.’ Canaries were used as an indicator species for the mining industry. Canaries are very sensitive to methane and carbon monoxide. Early mines did not have ventilation systems and could be very dangerous. As long as the canaries were singing, it was safe.

American dippers are very sensitive to pollution and are only found on rushing, unpolluted streams.  They look for streams with rocky bottoms and overhanging banks, and areas with adequate nesting locations.  

If you were thirsty and lost, the sight of an American dipper near or in a stream is a sure indicator of good water quality.

Diver Extraordinaire

American dippers hang out near stream edges, bobbing up and down on long legs, and foraging aquatic insects and larvae, crayfish, and caddisfly larvae. They will also eat fish, tadpoles, mayflies, mosquitos, dragonflies, worms, and midges.

Suddenly, the dipper dives into the cold, rushing stream. The bird bobs up and down searching for prey. American dippers are great swimmers and will wade and move small rock as it hunts.

Diving gear

Moments later the dipper pops up very close to the dive location. How can it do that?

Dipper species have their own built in ‘diving gear.’ They have an extra eyelid membrane that allows the bird to see underwater. In addition, the bird can also close off the nostrils (with special scales) when submerged. Finally, their extra oily feathers may keep them warmer when underwater and help shed water quickly.

Diving makes dippers prey for large trout.

Migration

American Dippers are permanent residents for an area and do not migrate. They will move around an area to take advantage of insect hatches and find unfrozen water. Indicator species typically focus on animals that do not migrate.

Huge Song

Both sexes of this species sing an elaborate song year around. The song includes high whistles and trills that can be heard above the chaotic rushing water.

Nests

The American dipper builds an interesting rounded nest as well. The globe-shaped nest is built by male and female birds. It usually on or near a rock ledge, river bank, under a bridge, or even behind a waterfall.  The nest will usually have a side entrance near the water.

The birds dip grass and other materials into water before adding them to the nest. The outer mossy layer is 8-10 inches in diameter and absorbs moisture. Coarse grass helps keep the inside 2-3 inch in diameter chamber dry. The inside chamber also includes leaves and bark.  The female typically incubates 2-4 white eggs. The male helps to feed the young which fledge in about six weeks. Streamside territories are fiercely defended.

REFERENCES:
–Oregon Department of Fish and Wildlife (https://www.myodfw.com)
–Wikipedia, American dipper (https://en.wikipedia.org/wiki/American_dipper)
–All About Birds, American dipper (https://www.allaboutbirds.org/guide/American_Dipper/)

American crow (Corvus brachyrhynchos)

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American crow (Corvus brachyrhynchos)

The American crow, the more you know about them the more interesting they are. Crows are a large, intelligent, all-black bird with a hoarse, cawing voice that is familiar over much the continent.

They are common sights in treetops, fields, and roadsides, and in habitats ranging from open woods and empty beaches to town centers. These birds are inquisitive, somewhat mischievous, and good learners and problem-solvers.

They usually feed on the ground and eat almost anything, including earthworms, insects and other small animals, seeds, and fruit as well as garbage and chicks they rob from nests.

Communal Roosting 

American crows are very social, sometimes forming flocks in the thousands. In the winter, American crows congregate in larger numbers to sleep in communal roosts.

Roosts can consist of a few hundred up to two million crows. Some roosts have been forming in the same general area for well over 100 years. 

Mobbing

American crows will work together as a group to harass or drive off predators, a behavior known as mobbing. This interesting video features a crow solving 8 puzzles in a row in order to reach food.

The crow has also been the subject of Native American legends, including this one: http://nativeamericans.mrdonn.org/stories/raven.html

Canada Goose (Branta canadensis)

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It is hard to imagine the familiar Canada goose population in danger. But, in the past, Canada geese were almost wiped out in North America.

The population has rebounded to the point where Canada geese are Oregon’s most familiar bird. For some, they have become Oregon’s most familiar nuisance.

Canada Goose with goslings,
courtesy ODFW.

Not All the Same

There are 11 subspecies of Canada goose that vary in size and color. All have the same long, black neck and white chinstrap. Five of those species are available for harvest (See Oregon Dept. of Fish and Wildlife for permit information.)

Territory & Habitat

Like other swans, ducks and geese, Canada’s are found on every continent and are common to Oregon. They congregate near water, such as reservoirs, lakes, ponds, large rivers, and native wetlands. They have overrun most Eastern native wetlands, including the National Wildlife Refuges created to protect the migratory populations and diversity.

In the past, most Canada Geese migrated to central and southern North America. Now more are resident and live in or near humans year around. The US FWS report that resident birds cause the most problems. Resident and migratory populations have separate breeding ranges and do not typically interbreed.

Diet

Canada Geese are one of the few bird species that can digest grass and primarily eat green vegetation. They also eat aquatic plants and grains, and fish and insects and will pick food off of the street and out of garbage cans.

They have become a serious pest parks, golf courses, farm fields, and airports. Not only can they damage crops but also foul pastures with waste. In addition to farm damage they provoke public nuisance complaints which the U.S. Fish and Wildlife Service (FWS) says are increasing every year.

Raising Young

Goslings (or baby geese) are raised near water. Parents lead goslings to water shortly after being born (great photo opportunities!). After just one day the goslings can dive up to 40 feet under water for food. Goslings can dive or swim away to escape predators.

Canada Geese have oily feathers making them well adapted to swimming, floating, and diving.

Adults aggressively protect their young and will attack anything, including humans, that they perceive as a threat. These are large birds that can be up to 20 pounds, stand 30 to 45 inches, and have a wingspan up to 75 inches). Aggressive behavior can include vocalization, hissing, biting, chasing, and more.

When goslings have learned to fly and the parents have finished molting, the whole family will leave the nesting grounds and find more productive feeding areas. This usually occurs in the late summer before massive southward migrations begin.

Conflicts & Solutions

Sometimes these inappropriate feeding areas are near airports. The Federal Aviation Administration (FAA) estimates there are 240 goose-aircraft collisions annually nationwide. Remember the 2009 US Airways flight 1549 that went down in the Hudson River? It was also traced to migratory birds.

Canada Geese are a protected species under the Migratory Bird Treaty Act.  A variety of management techniques may help deter the geese. Preventing public feeding, altering habitat, hazing, and other techniques have helped. Evidently, floating a silhouette of a nesting swan will deter the geese from an area.

Want more? See any of the excellent resources below.

REFERENCES:
–Oregon Dept. of Fish & Wildlife (https://myodfw.com/wildlife-viewing/species/swans-ducks-and-geese and https://myodfw.com/game-bird-hunting/species/geese)
–All About Birds (https://www.allaboutbirds.org/news/canada-goose-resident-vs-migratory/)
–American Expedition! (https://forum.americanexpedition.us/canada-goose-information-facts-photos-and-artwork)
–Why do migrating Canada Geese sometimes fly in the “wrong” direction? (https://www.allaboutbirds.org/news/i-thought-geese-migrated-south-in-the-winter-and-north-in-the-summer-why-did-i-just-see-a-flock-of-canada-geese-flying-in-the-wrong-direction/
–Wikipedia, Canada Goose (https://en.wikipedia.org/wiki/Canada_goose)