Monday, July 19, 2010

While Helen Waited

Our technique on the Short-tailed Hawk vigils has been to split up and watch from different vantage points. Helen and Noel have stayed in contact with handheld radios. We've each had marvelous encounters with wildlife.

Yesterday, the hours passed quickly for Helen, who found no end of entertainment with this family of Cliff Chipmunks.

Cliff Chipmunk family (Photo by Helen Snyder)

She wrote, "These little guys were at exactly the same stage of innocence as the young Short-tail on the other side of the ridge. On Saturday I watched him charging around the outside of a pine tree, snatching at terminal clusters of needles or pine cones––a crazy zig-zaggy dash that took him about 10 seconds, during which time he snatched maybe six times at imaginary prey."

How rich are these mountains, and how rich the hours we spend there!

The Monsoon vs Our Driveway


What a wonderful sight.

Sunday, July 18, 2010

Waiting for the Short-tails

A wait can be most engrossing. Today I returned to the Barfoot ridges in the Chiricahuas with Cathie Sandell, Christopher Rustay, and Noel and Helen Snyder, again watching for those two young Short-tailed Hawks and their parents. (Incorrigible, you say?)

At the very start of our vigil, Christopher spotted a fledgling Short-tail flying to a snag on a nearby ridge, prey clutched in its left talons. The buffy youngster perched for awhile, gazing around at the wide world, with no attempt to eat the prey it was carrying. Eventually the young hawk flew, and that was the last we saw of Short-tails for the day.

Pine Satyr, in the U.S. only found in the Chiricahua and Huachuca Mountains (Photos by Narca)

However, it was only the start of an interesting wait, high on the ridge. Hilltopping butterflies––Colorado Hairstreaks, Pine Satyrs, duskywings, cloudywings, sulphurs, blues, Weidemeyer's Admirals––lit in the Gambel's Oak and nectared at Penstemon.

In the U.S. Mexican Chickadees only inhabit Arizona's Chiricahua Mountains and New Mexico's Animas Mountains.

Eventually I wandered farther up the trail (although "trail" may be overstating it!) and found a good vantage point for a closer view of a ridge where the Short-tails like to perch. Several large, lichen-draped snags below my feet were home to a bustling family of Red-breasted Nuthatches, a pair of House Wrens, a family of Yellow-eyed Juncos, and the occasional Mexican Chickadee.

Red-breasted Nuthatch

Young Yellow-eyed Junco

As I hiked back, a sudden insect-like buzz announced the presence of a Twin-spotted Rattlesnake. The species is very rare in the US, and the Barfoot region is known for harboring one of the finest populations. Indeed, we hope that the Coronado National Forest plan will grant their habitat here some additional level of protection.

Twin-spotted Rattlesnake

And still we wait for the Short-tails...

Saturday, July 17, 2010


Yesterday Alan and I joined Helen and Noel Snyder for a Short-tailed Hawk vigil above Barfoot Park in the Chiricahua Mountains, and along the way we were distracted by a splendidly-colored Colorado Hairstreak, just emerged from its chrysalis and attempting to expand its wings.

Emerging Colorado Hairstreak (Photos by Narca)

The hairstreak is very scarce this far south, and I had never seen one before. Its host plant is usually Gambel's Oak, which thrives at higher elevations in the Chiricahuas. What a glorious butterfly!

Batman pose

Sunday, July 11, 2010

A Lingering Scaup

On Tuesday, July 6, Alan discovered a summering female scaup (!) at Willow Tank near Portal. Scaup identification is often challenging, and in this case we have an additional handicap: she is mostly flightless, probably due to wing molt, so we can't flush her. Therefore, the length of the white wing stripe––one of the few good field marks––hasn't been available to use.

Female scaup at Willow Tank (Photos by Narca)

So... is she a Greater or a Lesser Scaup? This scaup is showing some ambiguous markings. She has the tiniest hint of a white cheek patch, which female Greater Scaup can develop rather strongly in summer. But a whitish cheek patch isn't a diagnostic mark.

The shape of her head appeared good for Lesser Scaup in Alan's photos, yet when another birder studied her, he thought that the head shape seemed flatter and rounder. (He agreed that the shape in Alan's photos looked better for Lesser.) When I saw her, some head feathers seemed matted down, while others were dry and puffy, distorting the head shape––as you can see in these photos.

Her bill does seem more delicate and narrower than a Greater should show.

My favorite field mark can be tough to see. It's the width of the nail on the bill, and can require a very careful look, in good light. So on Wednesday Alan and I headed to Willow Tank, with scope in tow. The early morning light was exquisite, and eventually we routed the scaup from her cover in the waterweeds, and she swam to the center of the pond, where it was finally possible to see that the nail on her bill was narrow. Lesser Scaup. (And true––Lesser is by far the more common species in Arizona. Yet in early July neither should be here!)

Female Lesser Scaup at Willow Tank

What in the world is she doing in southeast Arizona in summer? Did an injury prevent her migration?

A postscript... she did finally fly for Jon Dunn and his WINGS group, confirming Lesser Scaup. This bird was tricky, though––Jon said that his first thought was "Why isn't this a Greater?"

Saturday, July 10, 2010

Of Orioles and Cowbirds

Normally Hooded and Scott's Orioles nest at our house. Bullock's Orioles come and go, but usually nest elsewhere in the Portal area––until this year. I've been really pleased in recent days to see a male Bullock's here at the house, carrying food. Then this morning, Alan spotted the focus of the oriole's concern: he was dancing attendance on a juvenile Bronzed Cowbird!

Bronzed Cowbird juvenile (Photos by Narca)

Female Bullock's Oriole finds caterpillar for cowbird

I went straight to the Birds of North America account, written and revised by Peter Lowther and Kevin Ellison, to see what more I could learn, beyond a general impression that Bronzed Cowbirds favor orioles as hosts.

Male Bullock's Oriole (Pen & ink by Narca)

The Bronzed Cowbird has only been known in Arizona for the past 100 years, and in the past 50 years its range expansion in the US has been vigorous, as land was cleared for agriculture and golf courses (a favored habitat!)––although, so far, nothing else has matched the tidal wave that we've seen of Eurasian Collared-Doves! Now there are scattered records of the cowbirds as far north as Canada.

Bronzed Cowbird's primary range in the US includes the Colorado River corridor between California and Arizona; about a third of Arizona; New Mexico from the bootheel northward a ways; southern Texas; and a small patch of southeastern Louisiana-southern Mississippi. Southward, their range reaches through Mexico and Central America to Colombia.

Their breeding behavior is interesting: the female cowbirds converge in areas of host nests, attracted by the songs of the host male. The Bronzed Cowbirds usually lay their eggs about a quarter-hour before sunrise and after sunset, and only need about 10 seconds to accomplish the job. Often several female cowbirds lay in a single nest within a 24-hour period. The timing is important, because the cowbirds must synchronize their egg-laying with the hosts' egg-laying. A study by M.D. Carter (published in the Condor in 1986) found that cowbird young did not survive if they hatched more than 48 hours after the host's young. Cowbirds often pierce any host or cowbird eggs already present in the nest, an action that could prompt the host to lay again and help to achieve synchronized hatching. Once a female cowbird has laid in a nest, she avoids returning.

Where Bronzed and Brown-headed Cowbirds overlap, host nests have been found containing the eggs of both species! A few host species like Couch's Kingbird, Northern Mockingbird, and Red-winged Blackbird regularly eject cowbird eggs, and Hooded and Orchard Orioles can foil access to their nests. Maybe that's why the Hooded Orioles in our yard will sometimes suspend their woven baskets from a hook (intended for suspended plants) under our eaves: I can just imagine the gyrations a big cowbird would have to go through to get an egg into that dangling nest!

Northern Mockingbird (Pen & ink by Narca)

Researchers found Bronzed Cowbirds laying in the nests of 101 host species, ranging in size from Green Jays to Golden-cheeked Warblers. The list includes Summer Tanagers, Red-crowned Ant-Tanagers, and Orange-billed Nightingale-Thrushes. Bronzed Cowbirds often bestow their favors on orioles, but where orioles are rare, they seem to favor finch hosts, like Northern Cardinals and Olive Sparrows.

Golden-cheeked Warbler (Pen & ink by Narca)

Sunday, July 4, 2010


The first hint of something extraordinary is all the activity along the South Fork road, just below the bridge. A dozen Black-headed Grosbeaks forage on the ground and munch breakfast in the branches overhanging the road. Apache Fox Squirrels nestle in the sprays of leaves. Acorn Woodpeckers are very busy, doing what they do best. A big Silverleaf Oak––one of the biggest I've ever seen––has produced a bumper crop of tiny acorns, and word of the feast has spread.

Acorn of Silverleaf Oak (Photos by Narca)

Normally Silverleaves are shrubs or small trees, associated with Madrean Evergreen Woodland. This giant stands about 40 feet high, with its roots well-watered by the nearby spring. (Google tells me that the national champion is 85 feet high, so our South Fork champ is just a teenager!) Like other oaks of arid climes, the leaves are leathery to resist water loss. The name comes from the leaf's silvery, reflective underside.

Underside of Silverleaf Oak leaves

In a good year, many animals thrive on the acorn crop, and last winter's El NiƱo rains have brought on a true bounty of acorns. I tasted one and it wasn't bitter––the amount of tannin in acorns varies with both species and individuals. Native Americans harvested acorns, prizing the best-tasting (such as Emory Oak), and giving special treatments to those that were bitter from tannin. This particular tree's acorns must be especially good-tasting, to attract so much attention from diners, while the surrounding oaks are ignored, at least for the time being.

Acorn Woodpecker caching food
(Mixed media by Narca)

Acorns alone don't account for the feeding frenzy happening today near the South Fork bridge. There also must be plenty of insects in the vicinity of the spring. Flurries of flycatchers––Brown-crested and Dusky-capped, Sulphur-bellied, Western Wood-Pewees––add to the tumult, while a male Blue-throated Hummingbird squeaks from the top of the Silverleaf and a Painted Redstart tumbles from tree to tree. An Elegant Trogon still maintains his territory near the bridge. Plumbeous Vireos, Bridled Titmice, and Brown Creepers search for food for growing nestlings.

Ahh, South Fork. How good it is to walk here again!

Friday, July 2, 2010

20-Minute Wonder

Yes, he was only here briefly, and yes, he only allowed for one quick photo through a hazy window... but Alan and I were thrilled to see this male Varied Bunting at our bird feeder on Wednesday! When we lived in Guadalupe Canyon, they were a frequent sight in the summer, and we followed the saga of their nesting, including one poor harried male pursued by a begging juvenile cowbird. But here in Portal they are much scarcer, and this male is the first we've seen in our yard.

Male Varied Bunting in Portal AZ
(Photo by Narca)