Sep
13

The Santa Cruz Flats

By Rick Wright

Hard to believe that it’s time already to start checking the Santa Cruz Flats, the low farmland along the river from Marana to Sunland Gin. Darlene and I spent several hours up that way today looking for shorebirds, raptors, and whatever else we might find.

The morning started well with two adult Harris’s Hawks perched at the end of the driveway, the first I’d seen in the neighborhood for several days. I don’t understand the peregrinations of that species in our area; we see family groups regularly in early spring and occasional individuals on and off at any time of year, but they have never become as predictable and reliable as they are at so many other places around town.

Happily, the Burrowing Owls at the not-so-secret secret location north of Marana have remained predictable, reliable, and cute as buttons. Today there were two huddled along the irrigation ditches, unperturbed by the crush of dove hunters working the owls’ fields.

A Loggerhead Shrike was also here; this is a favored site for that species all year ’round, and this bird was actively hunting the ground in an alfalfa field, fluttering along hoping, I suppose, to scare up a nice juicy grasshopper.

We knew better than to even try the Marana Pecan Grove this time of year–the risk of getting peppered is just too great when the kids are out shooting doves–but decided to check the hayfields just north for waterbirds. A juvenile Great Blue Heron stood patiently on a dry field, and a little gang of nervous Killdeer loitered on the road. Finally we ran across a flooded alfalfa patch; the only shorebirds were two Solitary Sandpipers–uncommonish in southeast Arizona–but the place was crawling with Plegadis ibis.

We counted about 165 birds, and though they went on alert while we set up our scopes (and some of them even flushed when a female Great-tailed Grackle swooped in low over their heads), they soon got back to the business of feeding, after a few minutes coming in very close to probe the slightly drier soil nearer the road.

A flock this big should, we thought, have included a Glossy Ibis or two, but all we were able to identify definitively were White-faced Ibis, with eyes ranging from reddish to scarlet and faces from pinkish to pink. A great many of the immatures (I assume first-winter birds) had simply brown eyes and dull gray-brown facial skin, and I suppose that one or the other of those might have been Glossies, but as so often when I actually spend time looking hard at Plegadis, I end up as uncertain as I was when I started. We did come up with two new questions, at least: is the base of the lower mandible from beneath pink in both species in winter? (It most certainly is in White-faced.) And does one species tend more than the other to white bars across the throat and neck? Grasping at threskiornithid straws!

But looking close did lead us to one discovery, a White-faced Ibis (red eye and pink facial skin) wearing a plastic band on its right tibia. It also appeared to have a silver ring on the tarsus, but the plastic band was legible: black on white, X26. I’ve sent a note to the banding lab and hope very much to hear from them just where this creature was hatched (I assume it was banded as a nestling, as most colonial waterbirds are).

The sun was warming, Turkey Vultures were rising, and it was time to go on. As we left, the ibis began two by two to assume their weird sunning postures, leaning dangerously to the side, one foot tucked, necks twisted and wings half-opened.

An ill-timed gust of wind could tip an entire flock!

The Red Rock feedlot was covered with lovely Brown-headed Cowbirds in all plumages, bathing in the puddles with a few Yellow-headed Blackbirds. Half a dozen Common Ground-Doves were along the road, but we didn’t pick out any Ruddys–they’ll be back soon. Watching over this scene of bounty was a Prairie Falcon, so shy that we assumed it had just arrived: they can be skittish all winter long, but this one pushed it to an extreme, playing leapfrog from telephone pole to pole as we moved slowly along the road.

And there were Swainson’s Hawks. The first were a barely visible half dozen, heads just sticking up above the tall alfalfa where they were hunting; soon we started picking them out of the sky above, too, and eventually we saw an assemblage hopefully following a ludicrously tiny farm truck along the edge of a cotton field. Our day’s count was well more than 50, an encouraging sign of things to come in the next couple of weeks. The autumn flocks in Arizona are always especially exciting for the diversity of plumages they contain; we saw several lovely reddish birds and a gratifying number of dark-morph individuals, too.

A few American Kestrels and Red-tailed Hawks, plus the occasional skyful of Turkey Vultures headed south, filled out our raptor list–until, that is, we got to Western Sod Farm. The sprinklers were on and the habitat irresistible, to my eyes at least, but not, unfortunately, to whatever grasspipers might have been in the area. Instead, though, we heard the strangest sound I think I’ve ever heard on those sod fields: the plaintive chirping of an Osprey. And sure enough, there it was, a still-wet juvenile bird low above the buildings, then perching on a pole to tear big chunks out of the small fish (!) it had caught. They show up in odd places in the desert this time of year, but Western Sod is one of the oddest.

Another out-of-place vocalization reached our ears at the PInal Gypsum Tank. While we were watching the Swainson’s Hawks, the unmistakably ear-splitting chatter of Tropical Kingbirds issued from the roadside pecans. There were at least two fledglings and an adult, pioneers pushing the range of this rapidly expanding species north. Tropicals do breed farther north on the San Pedro, but these were far and away the farthest downstream I’d ever encountered on the Santa Cruz. Interestingly enough, another was reported four or five miles away a few days ago.

Not a bad day on the Flats at all–and very different from the days ahead as this summer gives way to a beautiful fall.

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