BIRDING BY HINDSIGHT: A Third Look at Field Notes

Now that spring migration is over and the breeding birds are no longer singing like they did in June, you might as well hang up the binoculars until fall. Time for some light summer reading. So, for the third time — not just the second, as is customary in this Hindsight series of articles — let’s lie back in the hammock and take another look at the latest entries in my old ID notebook.

Some readers will recall there were two previous installments examining some of the contents of my field identification journal (http://mbwbirds.com/field-notes-i.html and http://mbwbirds.com/field-notes-ii.html). These entries, which began back in 1984, are notations on various bird identification revelations learned while out in the field.

The items in these first two articles included 16 years, as far as October of 2000, and at press time there was this loon causing some unresolved ID difficulties. Here’s an update:

• “10/12/00. Red-throated Loon: a juvenile seen on Lake Superior near my house; identified mainly by dusky area on throat and foreneck (which Pacific never shows?). Bird never seen to hold bill uptilted (seen on three different days) and bill shape not distinctive — therefore, tentative first ID was Pacific Loon. Also seen: pale gray head and nape (suggesting Pacific), no visible back/wings markings, white sides at water line sometimes present.”

I apparently had never seen or studied a young Red-throated Loon before, and my assumption was it would have the same distinctive bill shape and posture as an adult. Since it didn’t, and since I was initially unaware a juvenile Red-throated’s bill can look “normal” and Pacific-like, my first ID was erroneous.

• Though the next brief entry comes from Florida, it does have some potential relevance for Minnesota birders:

“April 2002, Florida. Snowy Plover very pale and whitish, much paler above than Texas birds.”

It had been years since I had looked at this species on the Gulf coast of Florida, and I had forgotten how pale they are dorsally. I was used to looking at Snowy Plovers from the West wintering in Texas: their upperparts are about the same shade as Piping Plovers — or even perhaps a bit darker. Though the Snowy Plover is only Accidental in Minnesota, there are at least eight records, so it will appear again. And when you find one, be sure to take careful note of its back and wing color, and we may then learn something about where this vagrant originates.

• One of the entries from the second article in this series referred to an unidentified duck, possibly a Black Scoter, seen in 1996. I’m still unsure what it was, and I was reminded of that when several observers saw this duck in Duluth:

“5/2/02. Unusually plumaged duck at Park Point — probably a hybrid or aberrant Bufflehead. Same body, head, bill size/shape as all adjacent female Buffleheads with it; same bill and eye color; crown paler; blackish-brown lores, around eye, and fading on ear coverts; crown, chin, neck, and chest dirty white; back and folded wings darker than sides; spread wings, legs/feet not seen.”

I’d still like to hear if anyone has any theories on the ID of this duck, or the one from 1996.

• Just as the Eastern Phoebe is widespread in Minnesota in summer, it also commonly winters in South Texas, and for the first time last fall I noted something about this familiar bird:

“November 2002. In Texas in winter, Eastern Phoebe has two calls I don’t remember ever hearing up north: 1) a short trill similar to Vermilion Flycatcher or Black Phoebe; and 2) a downslurred ‘teurr’ suggesting Lesser Goldfinch.”

When I asked other birders about this, one explanation was that these were contact notes between adjacent wintering birds. Since phoebes nesting in Minnesota are in separate breeding territories, contact between them is minimal, as would be any contact calls. But I am still curious if any birders here have heard phoebes in summer or migration giving any vocalizations other than their familiar “phoebe” song or their loud, sharp, single-syllabled call note.

• Though I have seen migrant Worm-eating Warblers several times in Texas and elsewhere, until this year I had somehow apparently never birded in their breeding range or heard one singing:

“April 2003. Worm-eating Warblers singing on territory on Sassafras Mt., South Carolina — a lifer song. Typical song softer, shorter, and a thinner buzzing trill than Chipping Sparrow. One song, however, had a Chipping Sparrow quality of trill, but not as loud or as long.”

Since this warbler is a highly sought rarity in Minnesota, I have had hopes of finding one here some year by first detecting its song. I now have doubts I could unerringly do this, though, after learning its song in Carolina. There are just too many Chipping Sparrows out there capable of varying their songs enough to sound like a Worm-eating Warbler.

• Speaking of warbler songs, I was reminded again this year both in Manitoba and here in Minnesota just how tricky heard-only warbler identifications can be:

“5/25/03, Gunflint Trail. Several Magnolia Warblers heard singing; not until someone asked me how to tell its song from a Chestnut-sided did I realize how similar they can be. Hard to explain and takes practice: Magnolia’s song (the one which drops in pitch at the end) is slower and has fewer notes than the typical Chestnut-sided, which is faster with the beginning notes run together more in a jumble.”

“5/31/03, Blue Mounds. Atypical warbler song heard and not IDed for several minutes until bird became visible — a Blackpoll. Song was run together into a trill, notes not separate as is normal; first thought it might be a weak Chipping Sparrow or Worm-eating.”

“June 2003. In Manitoba, Minn. and Wis., noticed again how similar other warblers can sound to Bay-breasteds/Cape Mays. Again at Paint Lake Cape Mays often sang alternate 2-syllabled song which I can’t tell from Bay-breasted. Blackburnian song can be variable enough to sound just like a Bay-breasted. Black-and-whites, even at close range, can sound 1-syllabled like Cape Mays, or short and weak just like Bay-breasteds.”

As I’ve already discussed with other birders on occasion, I remain skeptical of any heard-only reports of Bay-breasted and Cape May warblers in Minnesota and vicinity. There may be circumstances when such IDs can be made, but normally you need to see the singer to be sure.

• I’ve long been an advocate of looking at blackbirds eye-to-eye. It can actually help to sort through the ID of these birds by first and simply noting iris color: Common and Great-tailed grackles, male Brewer’s Blackbirds, and Rusty Blackbirds have pale eyes; female Brewer’s Blackbirds, Red-winged Blackbirds, and Brown-headed Cowbirds have dark ones. But I recently found myself taking a long and hard second look at this:

“5/31/03. Female Great-tailed Grackles feeding on berm of Hills sewage ponds seemed to have dark eyes, even through scope! First thought the light conditions were tricky (they weren’t) or they might be dark-eyed juveniles (wrong for this time of year), but after watching them closely their eyes changed at times from dark to pale. My only theory is their nictitating membranes were closed to protect their eyes as they fed in the grass, making their pale eyes seem dark?”

“June 2003. At Felton Prairie a female Brewer’s Blackbird was seen with both eyes pale, not dark!”

Like most Minnesota birders, I’ve felt it natural and safe to assume that any large-tailed grackle in Minnesota is a Great-tailed: the relative possibility of a Boat-tailed here is simply too remote to consider. However, it was definitely sobering for a few minutes to observe what appeared to be some adult dark-eyed grackles in Minnesota — which would have had to be Boat-taileds.

And, regarding that female Brewer’s Blackbird, I was reminded of another pale-eyed female in my yard back in 1984. (This bird and a dark-eyed juvenile Rusty Blackbird were included in the first article in this series.) I also note that Sibley’s field guide mentions under Brewer’s Blackbird that an “occasional female has pale eye.”

• Whether you want to call them intermediates or hybrids, look at enough Western and Clark’s grebes and you are bound to encounter some that are in-between and hard to classify. I had an excellent study of one of these last month:

“June 2003. Another intermediate grebe in ND: both sides/flanks pale like a Clark’s, and it repeatedly gave the 1-syllabled call like Clark’s. But both sides of bill dull greenish-yellow like Western. Face pattern in-between on both sides: black cap down to top of eyes, lores white with narrow black line below lores between eyes and bill.”

Over the years, I’ve noticed a few other Western/Clark’s grebes that I certainly have to assume were hybrids. Looking at one side of them, their bill color, face pattern, and flank color would all be typical for Clark’s; then they’d rotate around and their bill, face, and flanks on the other side were entirely typical for Western! My advice when dealing with these grebes is two-fold: first, be prepared to leave some as unidentified (like the one last month in North Dakota); and second, before identifying a Clark’s here, always try to see it from both the right and left sides to make sure it’s not a “Mid-Western” grebe.

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OK, bedtime story-time over. And if you’re still awake, it’s time to turn in and dream of fall migration. Oh, wait, come to think of it, it’s already here: I saw my first southbound Pectoral Sandpiper back on June 21. You’ve already missed a month of migration.