THE CHANGES OF FALL 

Wednesday, September 03, 2008

Is it September already? It seems like only last week that I was out with binoculars and camera tracking down spring warblers as they flitted from tree branch to tree branch, always seeming to disappear into the dense foliage before I had a chance to determine their identity. Birding by ear is crucial in the spring given the speed at which the trees emerge into full foliage.  

But there are signs of autumn about us right now. Numerous reports of migrating warblers are coming in right now. As of last week, bird banders at Prince Edward Point were seeing Tennessee, yellow, magnolia  Cape May, yellow-rumped, Blackburnian, bay-breasted, black-throated blue, mourning, and northern waterthrush. I am sure the species list has increased in content even more since then as the tempo of the fall migration of passerines accelerates.  

The real harbinger of fall though is the yellow-rumped warbler, AKA the myrtle warbler, and I noticed a few out at Sandbanks Park just two weeks ago. Look for them around your doorstep, window sills - wherever insects are apt to lurk during the cooler days of autumn. Amazing little birds who start out the year being almost entirely insectivorous, and being one of the last warbler species to finally disappear in November, merges into a diet of spiders, then resorting to red cedar berries when spiders are no longer available. No longer do they boast their colourful spring plumage, but rather, look more like sparrows with splashes of yellow on the rump and wings which flash during flight. Other species of warblers can’t handle the disappearance of insect food, so they must head south before the cold weather approaches.  

Other warblers are here too, and those who are into “confusing fall warblers” as Peterson in his field guide so thoughtfully calls them, have been racking up long lists of returning species. For that is what they are doing - returning, from their more northern breeding grounds, concentrating at points of land in Prince Edward County before chancing the long trip across the open lake. This is why Prince Edward Point, indeed, the entire south shoreline up as far as Sandbanks and beyond, is so important as it is a refueling station for millions of migrating birds before attempting the lake crossing, and equally important as spring migrants cross the lake and seek out areas of food.  

But like the yellow-rumped warblers, most of the 35 or so species of warblers that pass through have also lost their spring garb, and they have lost their spring song. Identity becomes a challenge when only a wing bar or off-coloured bill serves as any clue as to what’s up there on the limb. With fall plumaged blackpoll warblers and bay-breasted warblers the whole process of identity becomes very personal as we must examine their legs for subtle differences. But in the spring, the two birds are as different as night and day, and their songs while similar, have enough variation in their delivery to be separated easily.  

For those who revel in the ability to identify birds by voice, the entire process in the fall becomes a supreme challenge as few birds utter much more than a variety of call-notes. Habitat sometimes helps, but birds frequently become displaced in foreign habitat when migrating. Right now, too,  the roadsides and fields are teeming with sparrows as they feed on  the seed crop. But you must be quick when identifying them as their eyesight is excellent.  

There are lots of different colours out there right now. The male goldfinch is one of the better known species that throws off his gaudy spring dress and assumes the more sombre tones of the female. Shorebirds are also in fall plumage right now, at least most of them. Check out the semipalmated plover who retains his sleek killdeer-like plumage. But the scarlet tanager is an odd sight as he slips into fall plumage, retaining blotches of red as though splattered in blood.

Through all of this, it comes as some relief when we fire up the bird feeders and see chickadees, nuthatches, blue jays and woodpeckers looking like the bird books say they're supposed to look like, making us realize that come spring, all those drab birds we found in the woods and along shorelines will be back in spring plumage themselves.