In mid-November 2002, several of us visited Goat Island just above Niagara Falls to look for an unexpected bird visitor to Western New York. Among others already there when we arrived was Bob Andrle. He told me he had a good look at the bird we sought, and others agreed.
But when I looked out over the water, all I could see was a flock of rough-winged swallows. The rough-wings were not common that late in the year, but they seemed to be doing well hawking insects low over the water. Only after we watched for an hour did the rare bird finally appear. It was a cave swallow.
Even through my binoculars it looked like a cliff swallow, but local cliff swallows had all fled south more than a month earlier. Fortunately, observers with better eyesight than mine were able to record the special field characteristics that defined this rare bird.
Rare indeed. The cave swallow is a Central and South American species that extended its range into the Southern United States only during the last century. If you wanted to see one, you traveled to Carlsbad Caverns in New Mexico, where a few nested.
In about 1970, those local cave swallows began to increase in numbers and expand their range. They were soon found across southern Texas nesting in culverts and under bridges like their cliff swallow cousins. Then late in the century, vagrant cave swallows began to appear along the Atlantic coast.
Remarkably, they were next recorded, first in 1989, along the north shore of Lake Erie near Detroit. Those birds appeared to be moving east, so local birders kept an eye out for them. One morning in late 1999, Mike Morgante pointed out to a group of us a single swallow winging its way east along the Lake Ontario shore. The timing was right, as cave swallows had been reported in nearby Canada just days earlier, but we couldn't make out any field marks, and we missed being the first to record one of these birds locally.
Along the south shore of Lake Ontario, one was observed in 1999 near Rochester, two or three were seen in 2001, nine to 12 in 2003 and eight in 2004. All of those birds were flying west to east close to the shoreline or out over the water.
That set the stage for last fall.
Suddenly in early November the region was inundated with cave swallows. Given the weather patterns, knowledgeable birders were out and watching at Hamlin Beach State Park, and the movement was noted and immediately posted on the Internet. I joined a group of birders there watching as dozens flew by. From Nov. 3 to 6, 761 were recorded, and the Western New York season total was almost certainly well over 800 birds.
Unlike earlier years, these birds were flying a quarter mile inland from the lakeshore and they were flying east to west, often directly into strong westerly winds.
Other cave swallows appeared all over the Northeast. Perhaps the most remarkable of them was the exhausted bird picked up in Algonquin Park in Ontario by Ron Tozer and Dan Strickland. That bird later died, as did a few others in Rochester and Ithaca.
This remarkable event, an example in this case of famine to feast, leads naturally to the inquiry: What brought these birds here?
I'm sure that the first thought that occurs to most readers is hurricanes. And indeed southern and oceanic birds are sometimes moved north in the eye of such storms. In 2003, for example, Hurricane Isabel brought oceanic storm-petrels to Lake Erie. And last October Hurricane Wilma, after bruising the Yucatan Peninsula, crossed Florida and sped offshore up the East Coast to Atlantic Canada.
However, most ornithologists doubt that Wilma brought these swallows to the Northeast. There is a Caribbean cave swallow subspecies that has begun to appear in south Florida. Since Wilma passed over Florida before heading north, you would expect that subspecies to be represented, and that seems not to be the case. It is far more likely the birds observed locally arrived on strong fronts from the southwest on days preceding the observations.
I join Alice in considering this series of events "curiouser and curiouser."