Showing posts with label irruptive. Show all posts
Showing posts with label irruptive. Show all posts

Wednesday, May 20, 2009

In the backyard... Evening Grosbeak

Evening GrosbeakEvening Grosbeak, male, Forest Grove, Oregon on 15 May 2009 by Greg Gillson.

 

This large, stocky finch breeds widely in the forested mountains of the Pacific Northwest, where they feed on pine cones and other fruit, seeds, and insects. In winter, these birds often move to lowland towns throughout the region. However their winter travels are irregular and unpredictable. Some winters they may be common at backyard feeders. In other winters they may be absent.

Each May, however, these birds descend en mass to the lowlands west of the Cascades. Here they feed on the buds and young seeds of native maples and imported elm trees. At this time, they will move in and eat a tremendous amount of sunflower seeds at your feeder. By mid-June, most are gone back to the mountains, probably following the budding of the maples upslope as spring moves up the mountains.

Throughout the year, their loud, descending whistles (both clear and buzzy) announce their presence. However, many times they are glimpsed only in noisy flocks of 6-30 birds flying high overhead.

The bold white patches on the black wings really stand out on both sexes. The males have a smoky black head that pales into the yellow underparts. There is a blaze of yellow across the forehead. The huge bill is bone white, but has a slightly greenish hue in summer. Females lack the black head, and the body plumage is more of a pale gray with only a hint of yellow.

The breeding range of Evening Grosbeaks is the Rocky Mountains from northern British Columbia south through western Mexico, across the boreal forests of Canada to the Atlantic provinces, south to the northern portions of the northern states. The also breed in Western mountains from British Columbia south to central California, including the Coast Range. In winter, they move south, regularly to Pennsylvania and Iowa and other states at that latitude, irregularly to the southern states in the United States.

Thursday, April 9, 2009

What bird is that?... Questions and answers

You have questions. Lots of questions!

This article starts a new feature. Send your queries about Pacific Northwest bird identification or behavior or other topics. I'll do my best to figure out what you saw. I'll do some research. Then I'll write an article to answer your question. If you have a certain question, no doubt others will, too, and appreciate knowing the answer. My goal will be to do one Q & A article each week, answering all the questions I receive that week. I'll just use your first name and city in my answers. If you send photos I will likely use them (perhaps cropping and adjusting exposure for the web) so others can see what you are seeing.

Send questions to me using this link: PNWBB Q & A

To get this started, and serve as a template for future Q & A's, Johnny in Sandy, Oregon agreed to help with the first batch of questions and he even supplied photos. Thanks, Johnny. Here we go...


Click for larger view "I had the arrival of a group of about 8 or 9 birds that I believe to be Pine Siskins, the day after the first Lesser Goldfinches came to my Njer seed feeder. The Goldfinches have not returned since the new guys took over. And they are constantly bickering and trying to keep everyone else from eating (see photos). Also these guys really put away the grocerys. They eat, go get a drink and eat some more. I don't know how they can fly the eat so much. Are they always like this, or is my flok simply a bunch of hooligans?"

Johnny
Sandy, Oregon

The tiny, goldfinch-sized Pine Siskins are heavily streaked with a strongly notched tail. In flight you can see the yellow wing stripe (Click photo for larger view). They are irruptive in nature, following food sources (seeds and budding trees); they can be unpredictably abundant one year, but perhaps absent or uncommon the next. They breed in the pine forests in mountains in the Pacifc NW, but descend to the lowland regularly in spring for the tree and flower buds. They may occasionally remain through the summer in the lowlands to breed if there is a reliable food source. They are highly social throughout the year, foraging in large flocks, often driving other larger birds from the feeder. In a few weeks they will likely disappear to the mountains. For more information, see Cornell Laboratory of Ornithology's web site on the Pine Siskin Irruption of 2008-09 that is happening primarily in the East. This article has many additional interesting facts about Pine Siskins.




Click for larger view "I had several new birds in my back yard yesterday. This one is a dead ringer for the female version of the Red Winged Blackbird, (even though it doesn't look at all like a black bird to me) that is on my backyard birds chart. Is It a Blackbird?"

Johnny
Sandy, Oregon

This is, indeed, a female Red-winged Blackbird. Although it may look like a large sparrow at first, its shape reveals its identity. The long, very pointed bill and flat forehead is common to the blackbirds, cowbirds, meadowlarks, and orioles, which are all in the same family. Sparrows have shorter, conical beaks and most have rather rounded heads. I will unabashedly point you to my Red-winged Blackbird photo album. Compare the head and bill shape of the males with the females. Then go over to my Song Sparrow photo album and compare the bill shape to that of the blackbirds.




Click for larger view "I had both of these guys in my yard yesterday. I'm pretty sure the yellow one is just a House Finch, but the other bird doesn't look like any I've been able to find. Look closely at the color around the eye."

Johnny
Sandy, Oregon

You are correct, Johnny, these are House Finches. The male is yellowish-orange and within normal range of color variation for this species. See our recent article on House Finches. The other bird is a female. I'm no expert on this, but the female appears to be suffering from the disease, avian conjunctivitis. Birds suffering from this disease display "red, swollen, watery, or crusty eyes; in extreme cases the eyes are so swollen or crusted over that the birds are virtually blind." This disease was first noted in the Eastern population of House Finches in the Washington D.C. area in 1994. It broke out in the West in 2004. For more information see the Cornell Laboratory of Ornithology's web page, House Finch Disease Survey.