Oh, oh... Molt again

Great-tailed Grackle, Hines, Oregon on 23 May 2009 by Greg Gillson.

 

Recently I was working through some photos from last year. Usually, after a photo shoot, I will immediately turn the best RAW shots into jpeg's and post those. Then, as I have time, I will work on the other shots and delete the (numerous) bad ones.

So, for instance, when I photographed this vagrant Great-tailed Grackle in the parking lot of a restaurant in Hines, Oregon, 15 months ago, I uploaded the best shot immediately. That left me with some shots like this one, above, that I am finally getting back to.

Even though I pulled the lens in from 400mm to 340mm it was not enough, as the bird was so close. As a result, the entire tail didn't quite make it into the frame. And there's this distracting yellow "something" pointing right at the bird's head. So, it is not a very artistic photo.

However, it shows something that I didn't realize at the time. This bird is almost exactly one year old. How can I tell? Molt limits.

Now I've been birding 38 years, and am just "getting into" understanding molt. So I sympathize completely if you don't find this as interesting as I do right now.

For most birders,... the brain fogs over at the mention of molt. -- Alderfer and Dunn, National Geographic Birding Essentials, 2007.

Last month I discussed this topic using a photo of a juvenile Brewer's Blackbird in molt. Today's post continues that discussion.

Even though this is a black bird, it is not completely one solid black color. Much of the plumage is rich black with glossy purple and green iridescence. However, many feathers on the wing and tail are dull brown.

Those dull brown feathers are retained juvenile feathers. Those are the first feathers this bird ever grew, probably in June of the previous year. Now, in the month of May, 12 months later, those original wing and tail feathers are quite worn. They contrast quite nicely with the glossy black feathers that were part of the pre-basic molt in the previous September.

In the next fall (2009) this bird will molt in new wing and tail feathers (and all feathers, actually) and be in definitive basic plumage. From then on, all through its life, it will undergo a complete molt each fall. Only during this first year and a half, can the age of this species be determined using molt limits.

Knowing the age of the bird tells us something about this vagrant. Even though this species is expanding its range, this young bird wasn't likely to be breeding this year. If it survives, it will likely migrate back south for the winter and possibly remain south to breed the next year (spring 2010).

Black-headed Grosbeak

Black-headed Grosbeak, Forest Grove, Oregon on 15 May 2009 by Greg Gillson.

 

Black-headed Grosbeaks are common migrants and summer residents throughout the Pacific NW. They arrive in May and are quite common in towns at bird feeders and in riparian areas and deciduous and mixed woods through September.

The male, pictured above, is rusty-orange on the breast and rump, yellow on the body, black on the back. It has a black head and black wings and tail with large white patches and spots. Males sing a clear, rapid, robin-like warble. Both sexes give a sharp pik call.

Females and young during the first year are duller overall (brownish and pale orange) with striped head ("chipmunk bird").

These songbirds take 2 years to reach full adult plumage. The immature male plumages have a more striped head and back than adults.

Do the Shuffle!

Juvenile Pied-billed Grebes, Fernhill Wetlands, Forest Grove, Oregon on 19 August 2010 by Greg Gillson.

 

Last month I photographed the sinking dives of a Pied-billed Grebe at Fernhill Wetlands, in Forest Grove, Oregon. This week I photographed two birds there, one of which is probably the same individual.

These two birds have been hanging around the ponds there. From a distance I noted that they were regularly holding out their wings. So I walked closer to investigate, obtaining the photo above.

I observed that the grebe (the bird farthest back) holds its wings out about 3 seconds, fluffs its back feathers and shakes its back and tail, as in the next photo below, taken 6 seconds after the top photo. [Click photo for larger view.]



This behavior is called "feather settling." It is one of a number of maintenance behaviors that presumably gives the bird comfort. Other comfort movements are yawning, stretching, and resting. Many behaviors in birds are innate--they are instinctively performed following a constant pattern. Feather settling is often performed by raising the feathers, shaking the body, flapping the wings, and finally depressing the feathers down into proper position.

This reshuffling of the feathers was performed several times alternately by both birds. In the photo below the other bird takes its turn (6 more seconds after the second photo above). [Click photo for larger view.]



I realized that I had seen this before, without really thinking about it. Rich Ditch recently photographed a Pied-billed Grebe with its wings out. Now I know what it was doing!

This also explains the bizarre "fuzzy gull" I photographed last week at the coast. The adult California Gull fluffed itself all up as you can see in the photo below. [Click photo for larger view.]



Then it shook itself and flapped its wings. [Click photo for larger view.]



This gull was very worn. The feathers of the tail has lost most of the vanes and the tips are just bare feather shafts. This bird needs to start its fall molt and replace its old feathers very soon!

Perhaps this gull is getting new feathers and they itch? That would explain a reason for feather settling, too. As a matter of fact, the juvenile Pied-billed Grebes are also going through body molt. Itchiness might explain the repeated feather settling they are doing.

In the backyard... Rufous Hummingbird

Rufous Hummingbird, Forest Grove, Oregon on 21 April 2010 by Greg Gillson.

 

The Rufous Hummingbird is common throughout the Pacific NW. Males first arrive along the southern Oregon coast in early February and reach Portland and the northern Oregon coast about the first of March. From then on through April reports increase northward, east of the Cascades, and into the mountains. Males arrive about two weeks earlier than females and set up a feeding territory that they defend vigorously against all other hummingbirds.

When the females arrive, they mate and then set up a separate nesting territory. Females take care of all nesting, incubation, and feeding duties.

Interestingly, Rufous Hummingbirds breed as far south as SW Oregon, but apparently not (or rarely) into northern California. Brookings, on the southern Oregon coast, seems to be the dividing line between breeding Rufous Hummingbirds to the north and Allen's Hummingbirds to the south.

Male Rufous Hummingbirds are cinnamon-colored with bright reddish-orange throats (see photo above). Some males also have green backs--thus appearing as Allen's Hummingbirds. Female Rufous Hummingbirds have green backs and lack the colorful throat, and are nearly identical to female Allen's Hummingbirds. In both cases, narrower tail feathers in the Allen's can separate them in-hand or with close-up photos at just the right angle.

Rufous Hummingbirds are most common in moist Coast Range forests and the west slope of the Cascades. They are found in other moist forests , riparian areas, and in towns throughout the Pacific NW. They feed on flower nectar and insects.

After mating, males generally depart into the mountains and start heading south to Mexico for the "winter." It is unusual to see adult male Rufous Hummingbirds in the breeding areas much beyond the first half of July. Females start migrating south in August and it is mostly immatures that are present in the Pacific NW from mid summer to the first week of October.

For instructions on making hummingbird nectar to attract them to your yard, and debunk some myths, see: Bird feeding... Hummingbirds that appeared here back in April 2009.

West of the Cascades, and in some towns just east of the Cascade crest, from Vancouver, British Columbia, southward, the Anna's Hummingbirds are found year-round.

Birdfest & Bluegrass Festival: October 9-10

RIDGEFIELD NATIONAL WILDLIFE REFUGE
HOLDS 11th ANNUAL BIRDFEST & BLUEGRASS FESTIVAL
Thousands of birders gather to celebrate the fall migration

WHAT:
Birders from around the country will be gathering at the Ridgefield National Wildlife Refuge for the annual BirdFest & Bluegrass Festival. Now in its eleventh year, the Festival celebrates the natural beauty and rich culture of the Refuge as well as the beginning of the fall migration and the return of the Sandhill cranes. The Refuge provides habitat to more than 200 species of birds and is an amazing showcase of birds in the Pacific Flyway. The mild winter climate and wetlands along the Columbia River create ideal resting and feeding areas for Canada Geese, Sandhill Cranes, Great Blue Herons, swans, shore and song birds, and a variety of waterfowl.

The two-day event offers activities for both avid and novice bird watchers. Scheduled organized activities include:

· Sandhill crane tours
· Raptor shows
· Audubon-guided family bird walks and bus tours
· Kayak and canoe tours
· Guided photography walks

In addition to the birding activities, there will be:
· Bluegrass bands providing entertainment
· A Birders’ Marketplace with great local food and bird related crafts and art
· Guided tours of the historic Cathlapotle village archaeological site

The annual festival is hosted by the Friends of Ridgefield National Wildlife Refuge, a nonprofit organization dedicated to supporting the Refuge through the sponsorship of programs that connect people with nature and restore important wildlife habitat.

WHERE:
Ridgefield National Wildlife Refuge is located approximately 20 miles north of Vancouver, Wash. Visitors should take the Ridgefield exit off Interstate 5 and drive three miles west to Ridgefield, where there are signs directing you to the Refuge.

WHEN:
Saturday, October 9 and Sunday, October 10, 2010.

For more information and a schedule of activities, visit www.ridgefieldfriends.org

Cliff Swallow

Cliff Swallow, Malheur NWR, Oregon on 29 May 2010 by Greg Gillson.

 

Cliff Swallows are rather common throughout the Pacific Northwest, especially near water east of the Cascades. In agreement with their name they do nest in colonies on cliffs, bridges, highway overpasses, under the eaves of barns, and in smaller numbers on porches and out buildings, especially in rural settings. They are not usually found in forest habitats or urban areas.

They need water nearby, as they build their nests of mud. Those nests are gourd-shaped structures--a mud ball usually with a protruding side entrance. The bird in the photo above is collecting one bill-full of mud at a time to build its nest on a cliff near the Buena Vista Station at Malheur National Wildlife Refuge in SE Oregon.

Field marks for this swallow include the compact shape with short square tail, creamy-tan rump, dark rusty throat, and pale forehead. It is the only swallow in the Pacific NW with a buffy rump. The call is rather grating.

As with all swallows, they primarily feed on insects on the wing. They often feed over water. Their bills are short, but very wide.

Cliff Swallows winter in South America. They first arrive in the Pacific Northwest by the first of April. Fall migratory flocks form in July and most birds are gone by the end of September, though some stragglers may remain, rarely to November.

Nature Journal: Sunbathing Cliff Swallows

Cliff Swallows sunbathing on a roof, Jackson Bottom Wetlands Preserve, Hillsboro, Oregon on 7 July 2010 by Greg Gillson.

 

We had a rather cool and wet spring. Thus, when it finally warmed up just after Independence Day [Editor's note to visitors: it always rains on all holidays in western Oregon.], I went out on the trails at Jackson Bottom one hot morning and found these Cliff Swallows sprawled out and panting on the roof of this wildlife viewing stand.

Why?

I got out my trusty reference guide, The Audubon Encyclopedia of North American Birds (1980) by John Terres.

It turns out all sorts of birds sunbathe, fluffing up their feathers and panting. Some take it to the extreme by flopping their wings forward wildly, gasping for air, while lying prostrate.

That seemed to be the case for the birds observed here, many of which were in a dusky juvenal plumage.

Why do they do it?

Terres' sources indicate that sunbathing benefits birds in several possible ways. Heat is absorbed (they were just cold and wanted to warm up); Vitamin D is produced; skin and feather parasites may move off the back and to a place where the birds can remove them. Some birds apparently sunbathe during the time of molt--perhaps it stops the skin from itching?