By Madeleine McDonald
(Note: click on any of the photos to enlarge them and see more detail).
1. October 2011, Hephzibah, Georgia. Photo by Liam Wolff.
First of all, this bird was photographed in October of last year, leading me to believe it might be a fall migrant. When you take a look at the bird in question (which is obviously a medium-small passerine bird), vireos and warblers may come to mind. Vireos have heavy, hooked bills, and most species are mainly drab, apart from some subtly-colored markings. Although the description of plumage coloration may ring somewhat true to our bird, we still don’t see the kind of bill that you would expect for a vireo. Moving on. Let's talk warblers. This bird is undoubtedly a warbler. Now we just need to narrow down our options. It looks like we are dealing with one of those “confusing fall warblers.” These include Yellow-rumped, Palm, Pine, Yellow, Blackburnian, Bay-breasted, Blackpoll, Tennessee, Magnolia, and Cape May warblers, along with Common Yellowthroat, all of which are in range for southern GA. (There are a few others that I won't include here just because I don't feel it's necessary to do so for this particular ID.) The “confusing” part of fall warbler identification is mostly caused by drab female and immature individuals. (Keep this in mind, since our warbler is both, you should be looking at these as you read on).
We can rule out Yellow-rumped and Palm since both are winter birds at this location. The auricular (cheek) looks too dark and well defined for Tennessee Warbler. The combination of facial markings, shape, and the behavior of perching high in a tree seem incorrect for Common Yellowthroat. We can also easily rule out Yellow Warbler due to the lack of an all yellow head, plain face, and eye ring. The lack of a grayish head and white eye ring eliminates Magnolia. We are down to Pine, Cape May, Blackburnian, Bay-breasted, and Blackpoll warblers. Pine Warbler sports bold eye-arcs and a dark, stout bill, which doesn’t match our mysterious suspect. Something doesn't seem quite right for Cape May either. They have a sharply pointed dark bill and streaking on the upper breast. In addition, in autumn Cape May Warblers can look very drab in the face, especially immatures; notice our bird's uniquely-marked face pattern: the yellowish supercilium (eyebrow), the gray cheek patch extending down to what looks to be the nape, all surrounded in yellow. We are down to a tricky trio of the "confusing fall warblers": Blackburnian, Bay-breasted, and Blackpoll. In this case, though, it's not going to be that tricky at all! We can eliminate both Bay-breasted and Blackpoll, leaving us with only one bird, our quiz bird, an immature female Blackburnian Warbler.
"How'd you get the answer so quickly?" you may be asking yourself. Assuming you have a field guide in hand or nearby, flip the page to Bay-breasted and Blackpoll. Study the facial marks on each. Notice how they both have an overall greenish coloration on the head and face, lacking the unique face pattern I discussed earlier. This pattern (check out the differences bewteen males, females, and immatures), is a distinctive characteristic of female Blackburnian Warbler, and although not as obvious as their male counterpart’s plumage, is still distinctly recognizable, even in a drab immature female bird like this.
2. May 2012, South Padre Island, Cameron County, Texas. Photo by Madeleine McDonald.
Your first challenge in this photo might have been just trying to spot the bird! Once that was accomplished, you could tell that this bird looked to be a member of the wading bird family. We can easily eliminate most (the egrets, ibises, Roseate Spoonbill, Wood Stork, etc.) because our mystery wader is much smaller and none of the named species look the way this bird does in flight. They all lack the distinctive pattern that our bird is showing on the back. Take note of how this bird is flying low over marsh grasses and reeds, looking like it is probably preparing to land in the middle of them. This behavior is typical in the smaller, more secretive species of herons, including Yellow-crowned and Black-crowned night-herons, Green Heron, and the two bitterns, American and Least. Size, the presence of a dark back with white lines, which our bird is showing, and overall coloration rule out the two night-herons. It’s the same for Green. We are left with our final two choices: the bitterns. A quick flip through the field guide reveals that American Bittern is much larger than Least and does not have that bright, distinctive buffy color and the dark back with white lines. So, which bird does? The brilliant, little Least Bittern.
3. February 2011, Canyon Lake, Comal County, Texas. Photo by Madeleine McDonald.
Hang in there, amigo, don’t freak out! (Even though that’s what I did when I was standing three feet away from this bird, continually clicking the shutter button, and having difficulty putting a name on it). Do what I said, not what I did! First, let’s decide what we’re dealing with and then we can narrow down the options. If you have any familiarity with sparrows in the family Emberizidae, this bird likely struck you as one of those, maybe even a bunting or longspur. The species that this bird resembles most are Savannah, Vesper, and Song sparrows, Lark Bunting, or maybe Chestnut-collared Longspur, all of which can be found in central Texas during the wintertime. If this were a Lark Bunting, the bill would be large and a blueish-gray color, the face wouldn’t be so smudgy, and there would be a bold malar stripe. The breast would also typically be streaked, and this bird’s is clearly not. So let’s rule out Lark Bunting. Just based on build and general impression, I feel we can also rule out Chestnut-collared Longspur, or all of the longspurs, for that matter. So, we only have three candidates left, and they all closely resemble each other. Yes, you’ve got the, “Oh great!” face on right now, I can feel it! Song Sparrow shows overall rustier coloration and is generally heavily streaked on the underparts (do you see any streaking on our bird?), with a grayish head and reddish-brown tones on the crown. Song might also have a slight eye ring, but not as prominent as the one on this sparrow. They also sport a longer, more rufous tail, which our sparrow doesn’t have. Savannah Sparrow looks quite a lot like our quiz bird, but one of the biggest differences between the two is the auricular (cheek) pattern; notice how our bird has a dark, half-moon marking that’s shaped like an arc around the cheek, looking like a backwards “J”. Not only does Savannah lack this marking on the auricular, there’s another big problem: where’s the streaking on the chest? Now, Savannah Sparrows are one of the most variable sparrows out there (right up there with Song!), but have you ever seen one with such a clean, light chest that shows no streaks? All of the possibilities we’ve looked at here have a streaked chest, and this bird doesn’t show any streaking, so you may be thinking to yourself, “what’s up?” Take a look at that creamy-ish blotch on the upper wing. Savannah doesn’t have that, and this is not a Savannah Sparrow.
So what are we looking at? This little bugger is a Vesper Sparrow, and although just about every mark that didn’t fit on the other species has a perfect place on this bird, there are two that don’t: the clean, unstreaked chest and the random white patch on the upper wing. Vesper would normally show a streaked chest, and I had never seen any ordinary Vesper with a random white patch on the upper-wing until I met this one! It’s important to remember that when something doesn’t quite fit together the way you’d expect it to, more than likely they’ll always be a reason for it. We are learning this more nowadays with hybrid, albino, and leucistic birds. Did it occur to you that this might be an aberrant individual? If so, then good job, cause you are absolutely correct. This bird is leucistic, which accounts for the out of place, whitish patch on the wing and the plain all-whitish colored breast. In case you are unsure about what leucism is, About.com has a pretty good page on it: click here.
About the author: With a lifelong interest in birds and a love for nature, avid birder Madeleine McDonald, 13, can’t remember a time when she wasn’t inspired and in-awe of the winged wonders of our world. For the past several years she has assisted people with bird ID on a popular online birding forum and in 2010, with the help of a younger sister, started a neighborhood birding magazine. A few of her immediate goals include: traveling more, expanding on ID abilities, and learning more every day, so she can continue helping others, (not to mention herself) with solving bird ID mysteries. There’s nothing quite like that “aha” moment when the pieces of the puzzle fit together perfectly. She is currently in the process of thinking about how to bring a long-time dream into a possible, future reality that would bring a fresh and exciting perspective to the birding world. Madeleine currently resides in Texas, where she has lived all her life, and where a new birding adventure awaits her around every corner.