Sketch and story by Tom Godin,
August 17, 2001

If you haven't seen your fill of warblers this year, don't despair. Mid August marks the beginning of one of the strangest warbler occurrences of the year. No doubt you have heard of the warbler wave, created in spring as masses of birds head north after a long vacation in the south. But, as fall approaches the wave that headed north draws back toward the south. Because of this flow and ebb action, similar to the movement of the surf, I think of this late summer retreat as the warbler undertow. And not unlike the force of a true undertow, it brings all manner of bird debris with it.

What is bird debris? By this expression I don't mean bird bits, I mean birds in strange mixed flocks, joined in a southward feeding journey. So bizarre are the bird associations formed during the undertow migration that I myself get into a frenzy trying to see all the species in one of these flocks. If you find yourself in a really hot swell you may see warblers you have never seen before. Even if the spring and summer have passed without sighting a single Townsend's Warbler I count on these warbler undertows to bring one, or several, right up to my window.

These warbler undertows follow no predictable path. In spring food sources for migrant birds are often limited to areas where the first greenery appears and places where the snow has melted. At these times birds must keep to these areas if they are to find sustenance. The fall warbler undertow doesn't have these restrictions. Due to an abundance of food sources for birds in August, from ripe fruit to insects and caterpillars, the birds can go anywhere they want. There is no killing frost or cold to deal with either as there is in spring. This free-for-all time of warmth and plenty allows hordes of little birds to migrate at a leisurely pace, scouring the trees around houses, down busy streets and other unlikely areas.

The warbler undertow began just a few days ago for me when out the kitchen window I heard the loud, insistent song of a yellow warbler. Yellow Warblers have now finished nesting and when they were in the middle of that activity their haunts were the creek side willow tangles. There are no creek willows outside the kitchen window only ornamental shrubs and other planted species. I knew that this singing Yellow Warbler meant that this year's warbler undertow was lapping at my yard.

I went outside to see what the current had brought to the property. Bear in mind that these warbler incursions can be anywhere from a few birds to a large flock. This event was of the small variety but that didn't diminish its importance. In the mountain ash tree near the step I focussed on yellow bird moving nervously in the limbs. As it shifted about turning this way and that I realized that I was looking at a Warbler that was totally out of its range. I saw a Warbler with a yellow bottom half and a coloured back much like an orange-crowned Warbler. On the face I saw a black mark, just behind the eye, in the auricular patch of the face.

As I looked at the visual information in front of me, from somewhere deep inside my brain where bird information is stored, a coin dropped and out came the name Kentucky Warbler. I don't know where the name came from or how I knew that the traits I glimpsed matched this particular bird. I had no idea what a Kentucky Warbler looked like. I can only surmise that in looking through the warbler section I had collected the salient traits of this bird on a somewhat subconscious level.

I had to see more. I walked toward the tree, as the bird had moved deeper into the foliage, but try as I might I was unable to get a clear view. Suddenly the warbler flew out the other side of the tree and disappeared over the greenhouse. I spent some time scouring the trees in the yard to get another sighting but I finally gave up.

I went into the house and flipped open the bird book to the Kentucky Warbler. I was surprised to see that it was marked just like the bird I had seen. The range of the Kentucky Warbler is the eastern side of the continent mostly in the United States, only occasionally in Canada. The likelihood that the Warbler I had seen was that particular bird was slim.

At this point I must say that I am not claiming to have seen a Kentucky Warbler. The glimpse I had was for a second only and not of the quality needed to confirm the sighting positively. The dark on the face could have been a cast shadow. I will never know. But this sighting showed the appeal of the fall Warbler undertow; one never knows what may appear.

I sat on the deck for at least an hour after my initial sighting hoping to see this mysterious Warbler again but these flocks usually move along never to return. I did get to watch a female yellow warbler as she searched through the same mountain ash tree for edibles.

The next morning as I sat at the kitchen table I saw a warbler fly toward the Hummingbird feeder, a totally bizarre activity for a Warbler. Warblers were moving through again! This bird was more co-operative than the bird of the previous day. Again and again it tried to land on the Hummingbird feeder. At times it pursued the hummingbirds as if trying to keep them from the feeder. Many times in previous years, I have noted particularly aggressive behavior exhibited by warblers during the fall migration. The Yellow Warbler I watched yesterday drove a Warbling Vireo right out of the yard then returned to continue its foraging in the trees.

This morning I had time to get binoculars on the hummingbird pursuer and identified it as a Nashville Warbler, a bird not known to nest in our area. The only place I've seen one this year was at Lytton in spring.

Warblers that might be seen during fall undertows are Yellow-rumped, Wilson's, Yellow, Nashville, Townsend's, Blackpoll, Tennessee, Orange-crowned, American Redstart, MacGillivray's, and Common Yellowthroat. And let's not forget, some birders may even see the occasional Kentucky Warbler

Unfortunately in fall, many Warbler go into a special plumage, some so cryptic as to make the most avid birders pull their hair out. Be prepared to see birds with such indistinct marking that their identity will remain forever unknown. This too adds to the mystery, excitement and frustration of the Warbler undertow. To quote myself when a passerby once asked me what bird I was looking at' "I have no idea! But that's what makes for an exceptional birding day!"