Nature Journal: Nest box double-take

Black-capped Chickadee, Jackson Bottom Wetlands, Hillsboro, Oregon on 13 July 2010 by Greg Gillson.

 

There is nothing unusual in the above photo. On the free Wednesday morning bird walk I lead, we encountered this Black-capped Chickadee feeding nestlings at a nest box at Hillsboro, Oregon's Jackson Bottom Wetlands Preserve. The nestlings were grown enough to meet the parents at the nest entrance to receive food.

What is unusual, is that White-breasted Nuthatches were feeding nestlings at this same nest box 68 days earlier (see photo below)!

White-breasted Nuthatch, Jackson Bottom Wetlands, Hillsboro, Oregon on 6 May 2010 by Greg Gillson. Click on photo for larger views.

 

Here is what John K. Terres has to say about Black-capped Chickadee nesting in his book The Audubon Society Encyclopedia of North American Birds. He says that incubation is by both parents, 11-13 days and that the young leave the nest when 14-18 days old. The incubation and fledgling period is nearly the same for White-breasted Nuthatch (12 and 14 days, respectively).

It appears that the nest box might have been unoccupied approximately 42 days between the nesting of the nuthatch and chickadee.

Mountain Bluebird

Mountain Bluebird, Rimrock Springs, Madras, Oregon on 14 June 2008 by Greg Gillson.

 

The state bird of Idaho and Nevada, these birds range from the higher portions of the Cascades eastward across the Pacific NW. In winter they depart from much of the Pacific NW, but can be found in mild winters in lesser numbers in southern Idaho, south-central Oregon, and southward.

The lovely sky-blue plumage of the male provides a bit of color to the duller greens, grays, and browns of the sage desert of the Great Basin, where they are often found in conjunction with juniper and aspen trees for nesting habitat. In the mountains they prefer meadows and open ponderosa forests.

They eat a variety of insects (especially grasshoppers) and berries. Often they sit on fence wires and sally out to grab insects and return. Or, they may hover along the ground chasing insects.

They are readily attracted to nest boxes. Bluebird nest boxes are 5 x 5 inches and at least 8 inches in height. The hole should be 7 inches above the floor and 1-9/16 inches in diameter, which will block starlings. The nest box should be placed 3-6 feet above the ground.

The call is a soft few note. The song is a whistled tru-lee.

You may also like to visit the web site of the North American Bluebird Society.

Deposit Comments

Mountain Chickadee nesting in "comments" box, Idlewild Campground, Harney Co., Oregon on 26 May 2009 by Greg Gillson.

 

Above is a photo from this spring. I found this Mountain Chickadee with a nest in the suggeston box at a trailhead. I thought it very humorous. Earlier in the day I had found another nest of this species in a more typical location--an old woodpecker hole in a ponderosa pine tree.

I am preparing more information on Mountain Chickadees for a post on October 19....

In the countryside... Western Bluebird

Western Bluebird in a clear cut, Hayward, Washington Co., Oregon on 16 May 2008 by Greg Gillson.

 

When I began birding in 1972 the Western Bluebird was near the bottom of a 30-year decline in population in western Oregon countrysides. In fact, they were nearly extirpated. For instance, winter bird censuses for the Portland Christmas Bird Counts (CBC) from 1935-1947 averaged 20 birds per year, with a high of 47 and a low of 5. From 1966-1976 not a single bluebird was recorded on the Portland CBC (Hubert Prescott, Portland Bluebird Trail, SWOC Talk, Vol 3, No. 2. 1977).

Causes of decline are complex, controversial, and not fully understood. Certainly the spread of House Sparrows in the Pacific NW from the late 1890's was a large factor. The demise of family farms and the conversion to larger edge-to-edge farming played a role, as did the conversion of farmland into residential suburbs. Widespread use of insecticides may have played a role after World War II from 1945, eliminating insects or causing harm to birds eating treated insects. Then, too, the European Starlings could also have hurried the bluebird's downfall after they arrived in western Oregon in the 1940's. Forest practices, namely clear cutting with complete snag removal, made the foothills unattractive to bluebirds.

There were a very few bluebirds remaining, however, on farms on some of the small hills in the Willamette Valley. From 1974-1976 Bluebird Trails started up in rural areas near Portland, Salem, Corvallis, Eugene, and elsewhere. Volunteers built and placed hundreds of bluebird boxes at regularly spaced intervals across rural areas, starting at known nesting sites. Small diameter entrance holes kept out Starlings and most House Sparrows. But Violet-green Swallows, Black-capped Chickadees, House Wrens, Bewick's Wrens and other cavity nesting birds competed for these boxes. And predation and vandalism was high. Nevertheless, bluebird numbers climbed.

Numbers have not recovered on the Portland CBC. Perhaps, because of the urban sprawl, bluebirds will never return to backyards in Portland. But in Corvallis, some comparisons can be made. The first 5 years of counts in Corvallis, 1963-1967, this count averaged 24 birds. The population crashed, perhaps due to disease and a harsh winter, in 1969. During a couple of subsequent years no bluebirds were found. In the 5 years after the Corvallis Bluebird Trail was started, 1976-1980, Corvallis averaged 54 bluebirds on the CBC. In the most recent 5-year period, 2003-2007, the average number of Western Blubirds on the Corvallis CBC was 263. Amazing!

More and more people in the general public are erecting specially designed bluebird nest boxes. Forest practices have changed a bit so that some standing snags are left after timber harvest. Bluebirds nest in old woodpecker holes in these snags out in the middle of a clear cut in the lower Coast Range and Cascade forests. And bluebirds are increasing because of it.

In the Pacific Northwest, Western Bluebirds occur in lowland farmlands with scattered trees away from European Starlings west of the Cascades in Oregon and Washington. They also like open pine forests on the east slope of the Cascades of Oregon and Washington and higher mountians of NE Oregon, SE Washington, northern Washington and Idaho. They like oak savannah and open dry woods in SW Oregon and northern California.

At the pond... Wood Duck

Wood Duck, Dawson Creek Park, Hillsboro, Oregon on 16 February 2009 by Greg Gillson.

 

Wood Ducks are medium-sized ducks--smaller than Mallards, larger than teal. The male's brightly-colored plumage gives off an iridescent sheen of blue, green, and violet. The sides are butterscotch. The chest is maroon. Bold white outlines separate the head, chest, and wings from each other. The head sports a large crest that can be laid back or erected prominently (as in the photo above). They eye is reddish-orange.

The female is similar in shape, but mottled brown. It does show a hint of a ragged crest. It has a unique white triangular mask around the eyes. Thus, while not as colorful as the male, it is striking in its own right.

Though unquestionably a colorful and exotic looking duck, the Wood Duck has an equally interesting lifestyle.

For one thing, this duck nests in tree cavities! It is sometimes quite shocking to be walking around in the maple woods near a lake in summer and hear the startling burst of wing beats overhead and hear the rubber duck-like squeaking of this bird flying away. Overhead, this duck displays a rather long squared-off tail in flight. Most ducks have short pointed tails.

Amazingly, when only a few days old, the tiny downy chicks drop ungracefully to the ground from their tree nest--sometimes more than 50 feet in the air! Then they run and waddle along the forest floor to the nearest water where their mother cares for them until they are older.

Wood Ducks breed widely near lakes, river backwaters, and ponds in lowlands from southern Canada to the southern United States, except not in the southern Rocky Mountains or Southwest deserts. In winter many migrate into Mexico. However, in the Pacific Northwest they are found in lower numbers in winter wherever water remains unfrozen. That pretty much means in ponds west of the Cascades and in the Central Valley of California. In the Great Basin they are found in winter along the unfrozen backwaters of the Columbia River and larger tributaries. They are found in Puget Sound, but not along the immediate coast or in salt water.

Wood Ducks readily accept specially-built nest boxes erected near ponds. These boxes may attract Hooded Mergansers, too, as they nest in very similar situations. Nest box plans provided by Ducks Unlimited.

In the backyard... Bewick's Wren

Bewick's Wren, Hayward, Washington Co., Oregon on 16 May 2008 by Greg Gillson.

 

During those rare sunny Northwest mornings in March one can hear the cheerful clear whistled notes and trills of the Bewick's Wren emanating from the roadside blackberry tangles. This can give residents (false) hope that winter may actually end in the rainy Pacific Northwest. Along with the Song Sparrow, Brown Creeper, and Ruby-crowned Kinglet, this wren is one of the first birds to start singing their spring breeding song.

While the Eastern populations of this spunky wren are declining, the range of the populations in the Pacific Northwest is expanding. It is quite common west of the Cascades from southwestern British Columbia to northern California. From northern California it is found eastward to Missouri and south well into Mexico. Additional populations occur east into the Appalachians. Though generally absent from the Great Basin, birds follow the Columbia River eastward through the Cascade range into the Columbia River Basin and tributaries in Oregon and Washington (Seattle Audubon BirdWeb), and the Snake River to Idaho (IdahoBirds.Net).

Bewick's Wren is a small bird with a long curved bill. It has a long, floppy, barred tail often held up high at right angles to its reddish-brown back. Most noticeable is the white eyebrow stripe. This bird differs from the buffy-chested Carolina Wren in the East by Bewick's grayish-white chest. The upper parts of Bewick's Wrens tend to be redder in the East, grayer in the Southwest, and darker rufous-brown in the Northwest (as in the photo above).

The habitat of this wren is brushy tangles in woodlots and over-grown backyards, chaparral-oak communities in northern California, brushy stream edges, and clearcuts in lower elevation forests. Bewick's Wrens nest in natural cavities and woodpecker holes, and will readily use nest boxes placed lower than 7 feet from the ground. They eat insects they glean by crawling through brushy tangles. They will come to your bird feeder if it is not too far out in the open... and if you offer suet.

At the pond... Tree Swallow

Tree Swallow, Fernhill Wetlands, Forest Grove, Oregon on 12 April 2008 by Greg Gillson.

 

The Tree Swallow is generally the first swallow to arrive in the Pacific Northwest in spring. In fact, in northern California it regularly winters in small numbers in the Central Valley and along the coast. West of the Cascades in Oregon and Washington it arrives in late January. Additional birds arrive throughout the Pacific NW through March and into April, when they can be found over many ponds hawking insects and inspecting nest boxes placed there for them or inspecting holes in trees over water for suitable natural nest sites. Most migrate south from August to October, but there are some mid winter reports in the Pacific NW, primarily along the coast.

Tree Swallows are widespread across North America. In summer they occur from the edge of the treeless tundra in Alaska and across northern Canada south to just the northern edge of southern California, Arizona, New Mexico, Texas and the Gulf States. In winter, as discussed, they occur along both US coastlines from Virginia to Florida to Texas, and southern California and along the Colorado River in Arizona, and from there south throughout Mexico to Guatemala, Honduras, and also in Cuba.

The Tree Swallow is a metalic blue above with blackish-brown wing and tail feathers and white underparts. They show a black mask. Females are duller than males. Juveniles and first year birds can appear quite brownish, but show the darker mask. The photo above shows an adult male in brilliant breeding plumage.

A similar bird in the West is the Violet-green Swallow. The back of Violet-green Swallow, seen at close range, is a shocking bright lime green. The side of the face is white (lacking the black mask surrounding the eye that Tree Swallow shows). In flight, the Violet-green Swallow has shorter, more triangular wings, and white rump patches that almost meet at the base of the upperside of the tail. Violet-green Swallows are much more likely to make their home in nest boxes in your backyard than Tree Swallows--unless you live right on the water.

Juveniles and dull first year birds might be mistaken for Bank or Rough-winged Swallows. Indeed, some Tree Swallows show a hint of dusky breast band. But the dark, well-defined mask is a primary clue to identification if well seen. Bank and Rough-winged Swallows do not nest in nest boxes, so any brownish swallows doing so are likely Tree (or Violet-green) Swallows.

In the backyard... Northern Flicker

Northern Flicker, Rood Bridge Park, Hillsboro, Oregon on 13 March 2009 by Greg Gillson.

 

Like the tale of the blind men describing an elephant, a new birder seeing this bird for the first time may be confused as to the identity of this unusual woodpecker. Will they note the robin-sized brown bird with black bars on the back probing on the ground with a long bill? Will they note the flashing orange wing and tail linings and white rump as it flushes away? Will they see a large white-breasted bird with round black spots and a black crescent on the chest sitting on their fence? Or will a person only "discover" this bird as an unwelcome spring dawn alarm clock, declaring its territory by drumming loudly and incessantly on their home's downspouts or siding?

This widespread woodpecker breeds in woods and forests across North America from the treeline of Alaska and northern Canada south to Cuba and through Mexico. They retreat from northern areas in winter. Two forms formerly considered separate species, Yellow-shafted Flicker and Red-shafted Flicker, were lumped in the 1970's into one species, Northern Flicker.

The breeding form in the Pacific NW is the "Red-shafted" form, with salmon-colored (pinkish-orange) wing and tail linings. The face is gray with brownish crown. Males, such as the one pictured above, have a red malar (moustache) stripe. The form found in eastern North America has yellowish wing and tail linings. The face is brownish with a gray crown and a red nape mark. Males have a black malar stripe. These forms intergrade in the Great Plains and western Canada. Birds from these intergrade zones show odd or contradictory combinations of facial markings or yellow-orange wing linings. These appear in the Pacific Northwest primarily in fall and winter. "Pure" Yellow-shafted Flickers are rare in the West.

Flickers spend as much time on the ground eating ants as they do on trees. You may attract flickers to your backyard feeders by offering suet or a peanuts. Flickers readily accept nest boxes built about 18-24 inches tall, with a floor of 7.25 x 7.25 inches, and an entry hole with a diameter of 2-1/2 inches about 14 inches from the bottom. Place nest boxes in the shade at a height of 8 feet or more. Search the web for "flicker nest box plans."