BIRDING BY HINDSIGHT: A Second Look at Field Notes

The first entry on page one is now sixteen-and-a-half-years old. It reads as follows: 4/6/84. Red-winged Blackbird singing on territory also gave a series of peeping notes I’ve never heard before, similar to Blue-winged Teal.

Now I admit this nugget of wisdom is hardly profound and now may seem trivial, but at the time I was impressed. Here was a common bird I thought I was completely familiar with giving a vocalization I had never noticed before. So I wrote it down. It is now over 16 years and 103 pages later and I’m still writing.

Some birders keep a journal with a narrative of their daily experiences in the field; others maintain a paper or electronic file of trip checklists. Instead, the notebook I keep has worn green covers with frayed edges, a duct-taped binding, and the words I.D. NOTES crudely lettered on the front. What I became interested in doing years ago was keeping track of ID information I became aware of from experience, while out birding in the field, information I wrote down before I could forget it. Here were things not learned from reading any field guides or other references, since they simply weren’t there at the time.

As I thumb through my notebook, I see there were periods lasting weeks or even months without an entry, times I was apparently learning nothing particularly new or memorable. So, I wonder, what I was doing in the six months between 7/22/87 (when I was trying to describe the Wilson’s Warbler chip note) and the next entry in January of 1988 (when I found something worth noting about mynas and bulbuls in Florida)?

I also notice entries of dubious validity which were later amended, appended, or discarded. (Vireo call notes were apparently giving me fits on 8/23/84: my scribbling on page 24 includes five crossed-out phrases and an equal number of inserted afterthoughts, revealing I kept changing my mind about the Warbling’s, Yellow-throated’s, Blue-headed’s, and Philadelphia’s call notes.)

Many of the notes involve vocalizations, which, after all, are generally difficult or impossible to learn from the field guides. Some of the pages are devoted to notes on birds in Texas or Arizona or elsewhere with which I was less familiar at the time. Other notes have turned up years later as items in this series of Hindsight articles.

What follows is a random collection of some of my other ID notes which have not yet found a place in any of the previous topics addressed in this series, although some of these might be included in a future article. Listed chronologically, this assortment of former “discoveries” of mine from years past will hopefully serve to keep you from being as surprised or unprepared as I was then if you encounter these same sights and sounds in the future.

4/7/84. Red-throated Loon still at Superior Entry (first seen 3/31). Even at a distance or in flight bill is clearly and consistently held up at an angle.

Some of the entries are ID points previously learned from field guides, other references, or other birders, but noted in the field for the first time. In this case I was surprised to see how easily the uptilted bill was visible at a distance and in flight. But at the time I was apparently unaware that a loon with a bill angled upward is not necessarily a Red-throated. Just a year later there is this note: Churchill tour, June 1985. Pacific Loons can hold their bills up like Red-throated Loon. (So can Common Loons, by the way.)

Subsequently, I learned to examine actual bill shape, not the bill position, in identifying a Red-throated Loon. The culmen (i.e., top edge of the upper mandible) is straight, while the bottom edge of the lower mandible itself angles upwards halfway out. The straight culmen combined with the relatively low and flat crown shape gives the Red-throated Loon a distinct profile, and the angled lower mandible combined with the uptilted bill adds to this unique head/bill shape.

So, for 15 years I thought I had it figured out. While an uptilted bill is not diagnostic, the fact remained a Red-throated “always” held its bill tilted upwards and “always” had a distinctive bill shape. Not so. The problem is that almost all my field experience with this loon has been with adults, and the bill shape on juvenile Red-throateds — and other loons — may not be fully developed. I am also beginning to learn from conversations with other birders that Red-throateds often hold their bills level.

At the time of the writing of this article it seems there is this loon swimming on the lake in front of my house that reminds me of the indecision I was having in 1984 with vireo call notes. Its plumage fits a juvenile Red-throated Loon, but I had initially and incorrectly assumed it was a Pacific Loon, which is more likely here in fall. It seems its nondescript bill shape and level bill position are failing to meet my expectations during the past three days, and as soon as I finish this article there will certainly be a new Red-throated Loon entry on page 104.

4/23/84. Pine Siskin gave a call note I’ve never heard before: a soft, squeaky, two-syllabled call which suggested a distant Water [American] Pipit.

I had forgotten about this not particularly significant experience until now, but what makes it more noteworthy is my entry 14 years later, from July 1998: Heard American Goldfinch giving a flight note that sounded exactly like an American Pipit. This latter goldfinch reference was mentioned in a previous Hindsight article (, but, again, I hadn’t remembered then that siskins can do the same thing.


I find it curious how two closely related species can give a note essentially the same as the unrelated pipit’s. The simple lesson here is if you are familiar with the American Pipit’s call and think you hear one that’s out-of-season or out-of-place, check to make sure there aren’t any siskins or goldfinches around. Incidentally, speaking of siskin sounds, a reminder that the same page discussing goldfinch calls in that Hindsight article mentions there are calls of five or six other species that a vocal flock of Pine Siskins can mimic.

4/30/84. Both Rusty and Brewer’s blackbirds feeding together in driveway (males and females). . .there’s a female Brewer’s with a dark yellow or light brown eye present.

OK, that message is clear enough: use caution when using iris color to ID Brewer’s females since their eyes may not be entirely dark. And now, fast-forward 13 years to this entry: Newfoundland 1997. Juvenile Rusty Blackbird with adult at Dunville; looked like fall adult but with dark iris! Note the exclamation point, and note how Rusty Blackbird iris color is also unreliable at times.

Caution in blackbird ID is also recommended when it comes to actual plumage, not just eye color: April 1999. Immature male Red-winged Blackbirds with virtually no red visible, even in flight. Plumage essentially all black. While even novice birders quickly learn not to be fooled by perched male Red-wingeds concealing their red wing coverts, more seasoned birders are probably unaware how hard the red can be to discern on some males in flight. The natural result is to assume one of these apparently all-black blackbirds must be a male Brewer’s or Rusty if iris color is not noticed.

1/7/85. Little Blue Heron immature can have yellow lores but bill and legs unlike Snowy Egret.

Now here was something noticed in Florida and certainly worth noting — even if the sentence is not entirely accurate. But it is true that some young Little Blue Herons can have pale yellowish lores, and the possible result is their misidentification as Snowy Egrets.

However, there are some problems with my methods to avoid making such a mistake. At the time I thought any small white heron/egret with a bicolored bill “had to be” an immature Little Blue Heron, since Snowy Egrets “had to be” black-billed. Not true: I have learned since then a juvenile Snowy Egret’s bill can appear bicolored with a pale base.

Also inaccurate is my assumption that a pale-legged heron/egret was necessarily a Little Blue Heron, since I thought all Snowy Egrets had black legs. While adult Snowys do indeed have all-black legs, juveniles can have legs which can appear all or partly greenish-yellow, just like a Little Blue.

3/10/85. Female (possibly immature) Red Crossbill at feeder with two narrow but distinct white wing-bars. Bars were about equal width (though lower bar may have been a bit wider).

I now suspect this was an immature male, but regardless of sex it’s easy to see how one of these variants could be mistaken for a White-winged Crossbill. I recall seeing such Red Crossbills a time or two since this 1985 sighting, but no further notes on this appear in my notebook. Currently, I’m uncertain how atypical it is for Reds to have wing bars; in addition, does this anomaly depend on the time of year, or on the sex or age of the birds?

Churchill tour, June 1985. Female Greater Scaups (some but not all) had a diffuse white spot on ear coverts; strongly suggested female scoters.

Here was another field mark I had previously become aware of academically but now studied in life for the first time. When present — which wasn’t always the case — this scoter-like head pattern on female Greater Scaup was being advanced as a diagnostic difference from Lesser Scaup. At the time I was eager to accept all the help I could get with scaup ID, but here was yet another field mark whose validity eroded as the years and more scaup flew by.

Eleven years later I was still clinging to this belief to some extent, although I had learned that female Lesser Scaup could have a smaller and paler version of this whitish auricular spot. As I boldly pronounced in the Hindsight article on ducks ( "Female Lessers never have as bold a spot."

Sadly, however, I should have waited a year before making such a brave — and erroneous — claim about female scaup head patterns: June 1997. Female Lesser Scaup with male in Stutsman Co., ND with obvious white patch on ear coverts! Note especially the exclamation mark, since for the first time I was witnessing the demise of a dearly held belief. Indeed, there is no difference after all in the ear coverts on Greater vs. Lesser scaup.

Churchill tour, June 1985. Heard "tic tic mcgreer" call of Virginia Rail for first time.

Here, at least, is something from my first tour to Churchill I haven’t had to retract — at least not yet. What I find interesting is how this call is described in the field guides and included on recordings, while at the same time it’s a vocalization I seldom hear. And I hear Virginia Rails a lot, but they’re always giving the “kiddick kiddick” call or that descending series of pig-like grunts or duck-like quacks. Even after all these years, I can remember hearing “tic tic mcgreer” a total of only two or three times.

What’s also interesting is this may be a Virginia Rail vocalization given mostly on the East Coast, rather than in the Midwest or Texas where I do most of my listening. At least the few birders from eastern states with whom I’ve discussed this seem to hear this call more than I do.

And since we’re on the subject of Virginia Rail calls, consider the following entry: North Dakota 1998. Heard Virginia Rail (also seen) doing a call note never heard before. It was a loud, single note suggesting a Sora or coot. Since 1998 I heard this atypical call again on one occasion, and it’s another example that birders still have much to learn about the calls of Virginia Rails and other members of this secretive group.

11/14/85. At Superior dump saw an adult gull at close range with sun at my back with the right iris dark medium brown and the left iris clear yellow.

This gull superficially resembled a Herring Gull, by the way, and that’s the ID I eventually settled on. But if I had only been able to view the right side of this gull and only see its one brown iris, I can only assume this would have been reported as an adult Thayer’s.

Here’s another example, also from the Superior landfill: 12/15/97. Adult Thayer’s with different colored eyes: left eye was amber . . . and right eye was darker amber or yellowish brown. (My notes fail to mention how I decided this was a Thayer’s Gull, but presumably its outer primaries pattern was unambiguous.) I also have memories of two or three other adult Herring/Thayer’s-type gulls with one eye darker than the other, and, with the ID of some gulls determined by iris color, here we have another reason to approach gull identification with awe and fear.

Other complexities of separating Herring from Thayer’s gulls (and Thayer’s from Icelands) appear with some frequency in my notes. Space limitations, however, preclude a complete analysis here of these ID problems — which, of course, is my way of saying I’d have no idea what I’m talking about if I tried to discuss them! Suffice it to say for now that various pages in my notebook include accounts of:

• an apparent adult Thayer’s Gull with a Herring Gull-like underwing pattern (or was it a Herring with a Thayer’s-like pattern?);

• an adult Thayer’s with both eyes yellow (which occurs more often than most birders think);

• juvenile or first-winter Thayer’s Gulls in early winter with paler bases to their bills (such a bill pattern is alleged to be indicative of Iceland Gull);

• a first-winter Thayer’s Gull with patterned, not solid-colored, tertials (which also is said to indicate an Iceland Gull);

• and various Iceland, Thayer’s, and Herring gulls with endless variations and overlaps in their overall sizes, head profiles, bill shapes, and mantle shades of gray.

Some year perhaps, when I get enough courage, all these things might be addressed in a future Hindsight article.

5/31/86. Heard a Willow Flycatcher at La Crescent with a different call note: instead of a rising "sprrit", it descended like an Alder — "spreurt"; had same burry quality of a normal Willow and not siskin-like as an Alder would be.

I can still remember hearing this bird’s call note, which sounded as much like an Alder Flycatcher as it did a Willow. Although I thought it was easy to separate the various call notes of these two Empids as well as their songs, my confidence was somewhat shaken here. While it could have been a late migrant Alder, I admit I decided to call it a Willow mostly on the basis of where it was: a thicket where I had found territorial Willow Flycatchers singing several times before.

And 14 years later my confidence was shaken again in the same county and in the same month: May 2000, Houston Co. At Shamrock L. [east of Caledonia] a Willow Flycatcher repeatedly gave "shreeur" Alder-like call notes; only because it sang a few times did I know it was a Willow. This experience certainly reminded me of that bird at La Crescent, and I can only conclude that Willow Flycatchers breeding in Houston Co. have a local variation in their dialect. At least I hope this is the case — if not, it’s time to give up on Alder vs. Willow flycatcher ID and go back to studying Thayer’s and Iceland gulls.

12/6/86. Immature Mute Swan’s bill is gray in fall but pink by spring — but not sure if different from other swans in winter. In fall Tundra’s bill is black at the base but mostly pinkish elsewhere with no clean-cut pattern or demarcation; in fall Trumpeter’s bill is black-pink-black with sharp demarcations. In spring there’s no difference in their [Tundra’s and Trumpeter’s] bills . . . and it’s unclear what difference there is in winter.

Some of my entries were notes taken at ID lectures or workshops, rather than field notes per se. In this case, there had been so little written on swan ID at the time that I was especially interested in this talk about swans at a MOU Papers Session meeting. Note that the speaker’s comments on bill patterns did not address whether there are any differences between the three species in winter and did not cover how a Mute Swan’s bill differs from the other two swans in spring.

Even today, I am aware of only a couple of useful articles on swan ID in birding journals, and these do not entirely explain the differences in bill patterns. Nor did that 1986 lecture. In reality, in fall the juvenile Mute Swan’s bill can be either gray or pink with a clean-cut small area of black at the base. This is unlike the young Trumpeter’s larger area of black on the base and — contra the lecture — unlike the mostly pink-based bill on the juvenile Tundra.

By late fall and winter, the young Tundra’s bill becomes broadly black-based like the young Trumpeter’s, so by then features other than bill colors are needed to separate these two species. By winter, though, the juvenile Mute Swan’s bill pattern is apparently enough like an adult’s so that it should not be confused with the other two swans. And the situation with young swans’ bills in spring is the same as in winter: the Mute’s is even more adult-like and different from the other two, while the then mostly black bill colors on Tundras and Trumpeters continue to show no useful differences.

March 1987 (Platte River trip). Very pale crane seen: buffy whitish overall, about as pale as immature Glaucous Gull, same color all over including wing tips, except for red cap.

Such abnormally pale Sandhill Cranes may be rare, but they show up annually at concentration points like the Platte River in Nebraska where cranes stage in essentially countless numbers. Obviously, these whitish individuals could easily and understandably be reported as Whooping Cranes by those who forget to look for the Whooping’s black primaries and different pattern of red on the head.

I’ve also noticed that under some light conditions a flying Sandhill Crane’s flight feathers, which are a darker shade of gray than the rest of the plumage, can appear almost blackish. Such light conditions can also make a flying Sandhill appear whiter than it really is.

But other birds besides abnormally pale Sandhills or Sandhill Cranes seen under odd light conditions are mistaken for Whooping Cranes. Any large white bird with black wing tips like a pelican or Snow Goose can get reported as one — it’s simply a matter of wishful thinking by someone caught up in the mystique of the Whooping Crane. This endangered species gets all the media attention, and naturally the public simply wants their “fifteen minutes of fame” by claiming to see one.

February 1988. Sprague’s Pipit has a beady black eye and tinge of yellow on cheeks (suggesting Grasshopper more than Vesper sparrow); pale, shorter, semi-thick bill (unlike American Pipit); quite mottled and pale above; very pale and grayish-buff below (not at all colorful) with a partial "necklace"; small head and thin neck (it often "craned" to look at us); body thickens and appears "bottom-heavy"; easy to see if grass is short and if you carefully stalk it — nothing else looks or acts quite like it.

Such were my first impressions from this species’ wintering grounds in Texas, the first time I had a prolonged look at one on the ground. Previously, most or all of my experience with Sprague’s Pipits had been with birds skylarking high over their breeding grounds.

Since 1988, I’ve had several more excellent looks at these pipits on the ground in winter and in summer on the northern Great Plains. And I would still say “nothing else looks or acts quite like it.” However, to that original description I would add this pipit has yellow on the lores, not just on its ear coverts, which contributes even more to a similarity to Grasshopper Sparrow. Also add that its mostly pale bill is actually two-toned, with the top half of the upper mandible dark.

To my eye, the Sprague’s Pipit bears only a superficial resemblance to the American Pipit, and I think too many observers get distracted by trying to compare and contrast the two. For one thing, too much time is spent looking for the Sprague’s pale leg color, which is usually impossible to see in the grass anyway. Besides, some American Pipits also show pale legs — and there is even an entry about this in my notebook from earlier this fall.

Of course, as pointed out in an earlier Hindsight article, all this descriptive information would have been unnecessary if the field guides had done their job in the first place with this species (see

Pt. Pelee trip, May 1988. Female Cerulean Warbler can have a greenish cap with grayish upperparts — very different from male.

This seems to be the first time I had noticed how relatively nondescript some female Ceruleans can be, especially when compared with a male. And note this entry was in spring — you can’t blame the Confusing Fall Warbler Syndrome for this potentially difficult ID. By the way, those greenish and grayish tones on the cap and upperparts of a female Cerulean are interchangeable: sometimes the cap is grayish, sometimes the upperparts are greenish.

The point is while some females look enough like a male to be recognizable, others do not, and this plumage is relatively unfamiliar to even more seasoned warbler watchers. So it’s not hard to see how one could be mistaken for something else, like a fall Blackpoll with dark legs. Or a Pine, if the distinct eyeline and supercilium aren’t noticed. Or a fall Bay-breasted, if the side streaking isn’t taken into account.

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Well, that’s it for the Reagan years, an administration they used to call the Reagan Revolution. And here have been some of the first entries of what was for me a revolutionary approach of sorts to bird identification. Another Hindsight article on this subject will follow and include my entries during the George Bush administration, 1989–1992. Then we’ll put to the test a paraphrase of that old adage: A bird in the handbook is worth two in the Bush years.