Wood Warblers: The Butterflies of the Bird World

Terry Sprague

Yellow Warbler. Photo by Derek Dafoe.
 






[This article ran in the April/May 2013 issue of The SCOOP.]

It is early morning during the second week of May at Prince Edward Point, the south-eastern tip of Prince Edward County. The trees along the groomed Point Traverse trails are wet from the overnight rain. Yellow warblers are everywhere, and the much sought after northern parula with its dazzling colours is so common as to be considered almost a nuisance bird. There are the finely marked chestnut-sided warblers, and as the sun works its rays through the mist, it accentuates their dazzling yellow crowns and chestnut side streaks.

This is a fallout, something birders dream about finding along the shores of Lakes Ontario and Erie – Presqu’ile Park, Rondeau Park, Point Pelee…and Prince Edward Point. There may be thousands of birds here this day as other warblers land throughout the morning, exhausted by the rainy, windy flight across the lake. Several golden-winged warblers hang by their feet like bats as they methodically search the undersides of the leaves for insect larvae. Black-throated greens gasp their wheezy notes, while black-throated blues call from deeper within the woods. A male appears in one tree, its pocket handkerchief showing on the wings in the form of delicate white patches.

American redstarts, their contrasting black and orange coats seem more appropriate for a Halloween evening, and not a spring morning. There are Tennessee warblers singing their staccato notes, yellowthroats casually feeding in the prickly ash as though they belong there rather than in a wetland. Palm warblers work the branches, their tails bobbing up and down as though the tracery of branches is too much for them to maintain proper balance. There are magnolia warblers - radiant against the rising sun, Blackburnians with their sunburst throats, ovenbirds and yellow-rumped warblers - the list goes on. In all, over 20 species of warblers have arrived en masse to this diminutive point of land, the first land mass these neo-tropical migrants saw upon arrival. 

These small passerines are on a remarkable journey that has taken them all the way from their wintering grounds in northern South America and Central America, and many will not stop until they reach the boreal forests where they will nest. Peninsulas of land that jut out into the open lake are staging areas where they will rest awhile, fatten up on the spring supply of emerging insect larvae, and then move on. After departing their refuelling stations, that’s when we start seeing them locally in our backyards and woodlots as they fan out and browse their way northward, feeding and singing, seemingly, for the love of expressing their joy of life. Only on territory, will the males get more serious with their song and try to attract a mate.

There is a standing joke among birders that Nashville warblers, Tennessee warblers and Connecticut warblers are easily identified by their song, since they sing with a southern or New England accent. Actually they are so named because this is where early ornithologists first discovered them, and named them accordingly. While birds clearly do have readily noticeable dialects, depending on what part of the continent you happen to be when you hear them singing, there is nothing about the song of the Nashville warbler that is twangy, or suggests booze and broads and slipping around.

That bird species often deliver songs differently is well known. It doesn’t really matter how a yellow warbler sings, we always know that it is a yellow warbler. Other warblers, too, have an incredible variety of deliveries, but we always know their identity because they have a certain tonal quality that is unique. Some warblers, like the northern parula, offer two totally different songs, and under what circumstances they sing one over the other is not clearly understood.

During a guided hike a few years ago, one person claimed she was having difficulty understanding me as she was from Toronto and was adjusting to my “dialect.” I know about dialects. I have heard people talk in New York City, and I could listen to the New England dialect forever. I am even aware that Ottawa seems to have its own dialect. But I wasn’t aware that the Prince Edward County did also. I don’t think the folks in Napanee have an accent, or those in Tamworth, Kingston or Harrowsmith. Perhaps they do, and I just don’t detect it.

Birds, too, have dialects. We can suppose that individual species understand each other well enough when proclaiming their territories, but whether a straggler of the same species that wanders up from the south is understood, we will never really know.

Songs of many species often incorporate arbitrary elements learned in the individual’s lifetime. The basic song is there, but the young birds learn details of their songs from their fathers, allowing variations to build up over generations. As these warblers return to roughly the same location each year, and residential populations begin to build over time, it is easy to see that birds could develop what could be referred to as a dialect, peculiar to their geographical nesting location each year to which they arrive.

What researchers have found though, is that some birds may be bilingual. They will sing the local song that has been passed on to them by their fathers, but may occasionally sing a second dialect that they apparently have learned from members of their species passing through and migrating farther north. Researchers have also learned that local birds produce a sound that carries best in a particular sound environment. So it would behoove a bird to hold on to the song it has learned from its father because this product of natural selection enables it to project its song the greatest distance possible, to attract that special single female when he’s looking for a mate.

Fascinating stuff indeed that we all too often fail to consider when we are watching these little butterflies of the bird-world flitting about the branches on their way to the northern forests. Think about their destinations and their songs when the warbler family passes through your backyard this spring. Consider, too, that only days earlier they had been associating with resident bananaquits and motmots in Costa Rica.

For more information on birding and nature and guided hikes, check out the NatureStuff website at www.naturestuff.net

Birders in May enjoying the warblers. Photo by Terry Sprague.

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