Sunday, August 23, 2009

Late Summer Movement

This August continues to surprise and excite. Normally a veritable snoozer of a month, our yard has been bustling with activity over the past few weeks.

The big story has been the persistence of Black-headed Grosbeaks (above) at the sunflower feeders. They stop off here for a snack during migration at least once every May and August. However, multiple visits during these months are infrequent. We hosted several individuals for a week in May of 2008, and have never experienced multiple visits in August before. This year has been drastically different. Only one May visitor was recorded, but I have seen individuals at least once a week from July 28 through this morning. All visitors were either females or hatch-year juveniles (their plumage is almost identical). Black-headed Grosbeaks are incredibly shy at first, fleeing at the hint of movement (or glare from my telephoto lens), so my success in photographing them has been limited. However, they become accustomed to humans after a few visits. The fact that I've managed to scare off the majority of those that I've seen suggests that several different individuals have come through, and that they're not sticking around for long. I don't suspect that they'll be coming through for much longer, but what a ride it's been so far.

A female Rufous Hummingbird guards the backyard nectar feeder.

A juvenile male Rufous Hummer guards the same feeder from atop a rose tree. Competition for this food source between several Rufous and Anna's Hummingbirds has been very high.

Rufous Hummingbirds are also representing in unusually high numbers. They typically arrive in early-to-mid March, hang around until May, disappear in June (apparently they don't nest locally), return in July, and are gone by the end of September. I began noticing more than usual last month. They've moved on since then (the males migrate ahead of the females and hatch-years) and we've since been inundated with females and juveniles. In conjunction with the Anna's Hummers, they managed to drink down four cups of sugar-water last week. And over this time, they've been vehemently attempting to establish control our two sugar-water feeders. Watching them chase each other around has been entertaining. Their activity has waned somewhat over the past week, indicating that some of the Rufous Hummers have moved southward. But plenty remain and will be entertaining us for the next few weeks.

I had been waiting around for the past month to see Western Scrub-Jay fledglings, and was finally rewarded today. At least two extremely loud hatchlings stopped by this morning with their parents. It was quite a sight. Oh, and did I mention that they were extremely loud? Those crazy jays. While I've been paying much attention to our neighborhood's offspring Dark-eyed Juncos and their Brown-headed Cowbird "brothers" (two of each now, see the previous post for details), I just recently noticed that the adult Juncos are going through their Fall molt. One male is currently missing his upper tail feathers. Yep, the seasons are a' changin'.

A juvenile Western Scrub-Jay ponders its suet feeder perching strategy.

A molting adult Dark-eyed Junco

Lesser Goldfinches (left) are all over the place right now. This was somewhat unexpected, as finches in general typically don't flock until mid-September. But I've heard reports of higher-than-usual numbers of Lesser Goldfinches in Western Oregon and Southwest Washington, so it appears to be a regional phenomenon. Today's tally of 24 was a record for August (the previous high of 15 was established two years ago). Finches are highly unpredictable and it'll be interesting to see what happens later this year. I'm currently seeing about 3-6 American Goldfinches at a time, which is about normal for this time of the summer (these numbers will increase to 30-60 at this time next month). Pine Siskins are scarce right now, although that's about par for the course for August as well. Their numbers tend to uptick in October. Interestingly, I've read recent reports of unusually high numbers of Evening Grosbeaks in the Coastal Range. Since a large number of them move to the valley floor for the winter, some are predicting a large winter irruption. This would be great, as I'm still waiting (patiently) to check them off of my yard list.

American Goldfinches: More on the way soon.

Next month is shaping up to be very busy and exciting. Unfortunately, I'll be crazy-busy with work as well, but promise to find the time to share updates.

Sunday, August 9, 2009

Juncos Raise Cowbirds and Other Yard Tales

Late July and early August is typically one of the least exiciting times of the backyard bird-watching year. The breeding season is over for most species and most fledglings are becoming self-sufficient. Natural food sources are in high abundance, so birds' reliance on feeders is minimal. In addition, it's too early for migration or post-breeding flocking, so the number and diversity of birds in the yard is also minimal. Given all of this, I've been very pleased with what I've seen over the past few weeks. With the help of a recent heat wave, yard activity has far exceeded my expectations.

A fledgling Dark-eyed Junco forages for seed with its father on a warm August morning

Last summer, we were graced with the presence of fledgling Dark-eyed Juncos. Juncos do breed here in the valley, but only in small numbers. It was nice to see that at least one pair decided to breed in our neighborhood again this summer. But I was literally shocked to see an adult Junco stuffing Nyjger seed down the throat of what at first appeared to be a large, plump juvenile finch. After a second, it dawned on me that the "finch" was actually a fledgling Brown-headed Cowbird. I had never witnessed cowbird parasitism before. Cowbirds are the only birds that lay their eggs in the nests of other species (warbler nests are frequent targets). The host species then (usually) raise the cowbirds as their own. While cowbirds aren't exactly my favorite species, I still found this incredibly interesting and exciting. A second fledgling cowbird made an appearance in our yard last week and both are now regulars in the yard.

A Dark-eyed Junco feeds a fledgling Brown-headed Cowbird.

A heat wave descended on Western Oregon a week and a half ago, sending temperatures into the low-mid 100's (it was 101, 105, and 106 at the beginning of the last week of August), and temperatures hung in the low/mid '90s for the next week. Not surprisingly, this meant that the bird baths were in almost constant use. Black-capped Chickadees have been a fixture at the baths, as have Red-breasted Nuthatches, both species of goldfinch and their young, House Finches, Western Scrub-Jays, and Downy Woodpeckers.

There are also signs of post-breeding local movements. A Black-headed Grosbeak visited one of the sunflower feeders early one morning during the heat wave. It is possible that this individual was fattening up before its migration. Just yesterday, the first White-breasted Nuthatch in over two years visited our shaded bird bath. It is possible that the unusually dry conditions forced him to look for water somewhere outside of his breeding territory. Bushtits are flocking in numbers of 15+ again. This is somewhat unusual, as the larger numbers are typically not seen until late September. Male Rufous Hummingbirds have dwindled somewhat in number over the past week (undoubtedly headed South) and have been replaced by females and juveniles. They and the Anna's are constantly fighting over the nectar feeders. Lesser Goldfinches have already increased in number and are eating more than their share of Nyjer and sunflower. It's just a matter of time before the American Goldfinches and Pine Siskins begin to flock as well.

A male Anna's Hummingbird tries to cool off in the 100-degree shade on an August evening

A fledgling American Goldfinch bathes on a sunny afternoon, as a Lesser Goldfinch watches

An unusual White-breasted Nuthatch stops in for a drink

A juvenile House Finch munches on sunflower seed

Despite the fact that we're still in early August, we've definitely passed the apex of summer. American Goldfinches are already beginning to molt (below) and it's just a matter of time before more migrants pass through and the flocking begins.