One of our foot trails at the nature sanctuary will forever be associated with a particular bird, a beautiful member of the warbler family called the Golden-winged Warbler. Twenty years ago, the species was not easy to come by in Central New York, but now they are virtually impossible to find – especially during the breeding season. Our nature sanctuary hosted one of the Golden-wing’s last known breeding territories in the region, but it has now been a decade since the last representative of the species relinquished its hold on the land. Sadly, we have no expectation that the species will return. It’s a strange thing when a species become regionally extinct and yet life for everyone and everything else seems to go on as normal. Then again, it’s hard to blame people for not caring about something they never saw, and quite probably never even heard of. Does it really make any difference if there is one less voice in the morning songbird chorus? I’d have to say yes, but I recognize that I’m probably in the minority.
Twenty-four years ago, I made my first visit to the land that would become Spring Farm CARES’ Nature Sanctuary. At that time, I had dedicated myself to making a complete list of all bird species found on the property. In pursuit of that goal I spent many early mornings walking through the various habitats – mostly listening for which birds were present and jotting them down in a notebook. On one June morning, on a south facing slope of an old bushy pasture, I was treated to the song of a Golden-winged Warbler. Honestly, it’s not what most people would consider a proper bird song, at least not one befitting such a dazzling species. Shouldn’t all beautifully plumaged birds be equipped with appropriately melodious songs? I personally think that it’s good enough if they have interesting songs. The Golden-winged Warbler’s song is a series of buzzy notes that some liken to the toneless trills of insects. Exemplary music or not, the Golden-wing’s song is distinctive. It consists of a long buzzy note followed by 4 shorter notes that are lower in pitch and just as buzzy.
It’s amazing to think of just how many birds that nest in grasslands and overgrown pastures have non-musical, low-pitched, trilled songs. Included in this “buzzing” crowd is the Grasshopper Sparrow, Savannah Sparrow, Blue-winged Warbler and Prairie Warbler. A bird called the Clay-colored Sparrow, which sometimes shares the same habitat with the Golden-winged Warbler, produces a similar buzzy song. The sparrow’s song consists of 3 to 5 buzzy notes, but these notes are typically all of equal length and all on the same pitch. Still, mistaking a Clay-colored Sparrow’s song for that of a Golden-winged Warbler has been known to happen. Birds that produce low trilled vocalizations most likely do so to increase the range of their broadcast. They prefer their territorial proclamations to be heard over long distances, and low frequencies carry farther than high ones. This is especially important in open areas where wind noise can substantially limit the distance sounds can travel. However, for a bird like a warbler (that weighs 8 to 11 grams), producing a low tone is not that easy. The small songbird’s solution to this problem is to trill or “buzz” out their low notes, and it seems to work. That’s probably why so many species do it.
It’s typical when conducting a bird censes to make visual contact with only a small proportion of the birds tallied. In most instances, identifications can be confidently made by sound alone. However, in this case, seeing the bird I was hearing was a must, since the Golden-winged Warbler often interbreeds with another closely related species called the Blue-winged Warbler and their hybrid offspring may sing the song of either parent. This means that in order to positively identify this species, it must be seen. I had no trouble convincing myself of this necessity; after all this was a cool bird – definitely eye candy. Fortunately, unlike the vast majority of the warbler clan, which never seem to cease flitting about in tree tops, Golden-winged Warblers will typically stay perched on an open branch when they sing. I say that, but on that day, I had a hard time getting a good look at the bird I was hearing. He had become highly agitated soon after I entered his territory. He started giving sharp warning notes and alternated them with loud chattering calls. It wasn’t me he had a problem with though. It turned out that he was actively defending his nest area from an intruder. When I finally saw the Golden-winged, he was in hot pursuit of a male Blue-winged Warbler. They darted through the bushes and undergrowth at great speed – both occasionally flashing their near-identical white tail spots (another sign of the two species’ close lineage). They flew back and forth in front of me several times, which indicated to me that I was standing at the center of a territory much coveted by both birds. Since it was the Golden-winged that was the more aggressive one, I figured that he already secured a mate and she was most likely on a nest somewhere close by. The fact that this was his nesting site gave him all the incentive in the world to be belligerent, and that he was in spades.
I was curious about this Golden-winged Warbler’s mate; was it a Blue-winged Warbler? Was it one of the named hybrids types (Lawrence’s Warbler or
Brewster’s Warbler)? In the case of both the Golden-winged Warbler and the Blue-winged Warbler, the females alone are responsible for incubating the eggs, so if this bird did in fact have a mate, she was most probably staying tight on her nest and I was unlikely to get a look at her. During that same time period, I had better luck in another area not far from New Hartford’s Sherrill Brook Park. There in an overgrown farm field, I came upon a most interesting family of birds. The male was a Golden-winged Warbler and his mate was a female Blue-winged Warbler. When I found them, they were busily feeding a clutch of young in a well concealed ground nest. I couldn’t actually see the nest, but I could clearly hear the begging calls of nestlings emanating from it. The young ones sounded loud and boisterous. They were probably over a week old and quite possibly close to leaving the nest. Both parents were frantically collecting food, which was comprised of protein-rich insect prey. While I was watching them make repeated trips to the nest, I noticed something peculiar. There was a 3rdadult visiting the nest and often moving in close association with one or the other parent. It was an adult Brewster Warbler, the more common of the two hybrid forms. I thought at first that the hybrid was also feeding the young in the nest, but that wasn’t the case. Instead it was actually trying to get the adults to feed it too! In other words, it was begging. This was highly unusual behavior. It was too early in the season for this adult plumaged Brewster’s Warbler to be an offspring from a prior brood of these same parents, and it seemed out-of-the-question that this family would’ve reunited a year later on this territory. Warblers (and most songbirds for that matter) don’t tend to retain their family ties after the breeding season ends. In fact, when the next breeding season comes along, the adults typically choose different mates and the young they once doted on become strangers – or at least that’s what we’ve come to believe. Certainly, I’d never seen this kind of thing occur with any warblers before or since.
These guys made for one interesting family – a true variety pack. Each member had their own distinct plumage. The male Golden-winged Warbler somewhat resembles a Black-capped Chickadee with his black throat patch, gray wings and gray back, but his golden cap and wing patch gave him a more regal look as if he might be the chickadees’ king. The female Blue-winged Warbler’s plumage is mostly yellow, but with blue-gray wings and thin white wing bars. A thin black eye line extends from her bill to her cheek. Her attire is a somewhat muted version of a male Blue-winged Warbler’s plumage. The Brewster’s hybrid more resembled the Golden-winged Warbler, but lacked any trace of the black throat patch. Instead of the patch on its wings there were 2 thin yellow wing bars. Also, its whitish chest had a light yellowish patch on it. This plumage was typical of what occurs when a pure Golden-winged Warbler and a pure Blue-winged Warbler produce offspring.
I’m used to songbirds like these warblers disappearing from an area due to habitat loss or due to one of the plethora of conservation challenges that migratory songbirds face, but the Golden-winged Warbler’s problems are compounded by this habit of breeding with another species. The Blue-winged shares virtually the same habitat requirements as the Golden-winged and since their breeding range overlaps, they are destined to interact; only when they do, the Golden-winged Warbler loses. For years, what I witnessed repeatedly throughout our region is that when Blue-winged Warblers arrive on Golden-wing territory, in a few years there are no Golden-wings left to be found. They are not killed or driven out though, instead they are genetically overwhelmed.
The two species are very closely related. Their appearance, vocalizations and behavior all make that abundantly clear. The fact that they produce offspring that are viable breeders is yet another indication of their genetic compatibility. Geological isolation in the not-so-distant past (perhaps only a million years ago) caused the two species to diverge from a common ancestor. Being brought back together is serving to reverse the process and merge the two species into one. One could argue that the loss of the Golden-winged Warbler by this kind of “genetic swamping” is not as bleak a thing as true extinction, since as long as the more dominate Blue-winged Warbler survives there is the chance that in some future epoch, isolation of a portion of the Blue-winged population may again lead to the inception of another “winged-warbler” variation – perhaps one not unlike the Golden-wing.
Our last Golden-winged Warbler at the nature sanctuary became something of a celebrity. Birders of the area regularly came to try and get a look at him and he was usually quite accommodating. Although his plumage was typical for a male Golden-wing, his song was not, so identifying him visually was the only way to confirm his presence. Regarding his song, it was indistinguishable from that of a Blue-winged Warbler. It was a double buzz, with the second note as long as the first, but on a lower pitch. Why did he sing the wrong song? That is a great question. Most likely, when he was not long out of the nest and learning to sing, he was heavily influenced by the songs of his Blue-winged Warbler neighbors. I’ve seen this phenomenon before in other songbirds including some that are not closely related to each other. I recall once finding a Field Sparrow that sang exactly like a Prairie Warbler. Again, in that case we were dealing with two species that had similar habitat requirements. It’s highly likely that the impressionable young sparrow had ample opportunities to be influenced by his vocal Prairie Warbler neighbor.
What was quite probably the last Golden-winged Warbler of Kirkland spent five breeding seasons with us. In that time he was never able to find a female of his own species with which to breed. Twice he bred with Brewster’s hybrids and twice with what were apparently pure Blue-winged Warblers. The fact is that there were simply no more Golden-winged Warblers of either sex, coming through the area anymore. The species’ demise, as far as this area was concerned, was at hand. Finally, in the year 2010, he failed to return and no other member of his species has ever again tried to hold that territory. Over the course of the last 50 years, Golden-winged Warblers are said to have experienced one of the sharpest population declines of any songbird. In the Northeast they are declining by an estimated 20% annually. The decline has been especially dramatic in areas where the Golden-wing and the Blue-winged Warblers’ ranges overlap. The stronghold for the species is now in the northern section of the Midwest including Minnesota where, so far, they seem to be rallying. However, nowhere should they be considered safe.
According to historical records, neither the Golden-winged Warbler nor the Blue-winged were present in New York State before the mid 20thCentury. In relatively close succession (only 2 decades apart) both species, first the Golden-winged and then the Blue-winged, expanded their ranges northward. They were coming in to take advantage of habitat that appeared when a significant amount of farmland was left fallow and allowed to grow in. Overgrown, bushy fields are necessary for both species’ nesting. The Golden-winged Warbler also requires the presence of mature woodlands adjacent to its breeding grounds – a detail that makes the species harder to satisfy than the Blue-wing. After the young leave the nest, parent Golden-wings need to be able to move their fledglings to the forest where they will continue to be fed until they become independent. It’s hard to overstate how important overgrown meadows are to certain wildlife species. Of course, habitat of this type is in the process of transitioning into young forest, and as it continues to mature it ultimately becomes unusable for the “winged” warblers. The Golden-winged Warblers are not the only bird species suffering population declines in the
Northeast due to the loss of this type of habitat. Other notables include the Brown Thrasher, Rufous-sided Towhee and Field Sparrow. Happily, these songbirds are currently doing well at our nature preserve and show no signs of going the way of the Golden-winged Warbler. The Blue-winged Warbler also continues to persevere. Their numbers are not as strong as they were ten years ago, but they are in no imminent danger.
To this day when I walk down the valley trail and see the American Elm tree where the Golden-winged Warbler once liked to perch, I feel a sense of emptiness. It’s similar to the feeling of loss one experiences when a family member dies. But aside from sentimentality, extinction (regional or world-wide), has consequences. Our native birds are not merely pretty feathered packages. They all have roles to play in the economy of nature and we ignore their plights at our own peril. Hearing the Blue-winged Warbler’s song emanating from a nearby tangle of Buckthorn Trees gives me some solace. Seeing one perched high on an open branch like a small yellow beacon; head tilted back as he unleashes his song with full gusto, I come to the realization that the Golden-winged Warbler is not quite gone without a trace. Part of it is right there in that yellow bird. Undoubtedly most, if not all Blue-winged Warblers in these parts carry with them at least some DNA of Golden-wings. That means that the Golden-winged Warbler is more tangible than the average ghost. There is some comfort in that.