Warblers, Shorebirds, Hawks - Birds on the Move

Nature Notes for September 30, 2011

In rambles around various parts of Northumberland County over the past two weeks, fall migration is very much in evidence. It seems, however, to be a week or two behind schedule.

The mix of warblers present at Presqu’ile Provincial Park last Sunday (Sept. 25) was what might have been expected at least ten days earlier. Black-throated Green Warblers dominated the flocks of warblers which we saw. They were accompanied by Blackpoll Warblers, Magnolia Warblers, Black-throated Blue Warblers, Nashville Warblers, Northern Parula, AmericanRedstart, and Chestnut-sided Warblers, all species which move earlier in the migration season.

Among the warbler flocks, Philadelphia Vireo, Red-eyedVireos and Rose-breasted Grosbeaks were also seen.

Perhaps the rainy, windy weather in late May and early June caused these species to lose their first nest. If they re-nested, there would be a corresponding delay in the growth of their offspring. This could be one reason for the late movement. The warm, wet weather may also have caused some birds to linger longer in the north.

Mixed in with the tardy migrants were the first of the later ones. A few Ruby-crowned Kinglets and White-throated Sparrows were found. The kinglets are en route to the southern U.S. and Mexico. A few White-throated Sparrows may winter in southern Ontario, but most winter south of the Great Lakes in the continental U.S.

Lincoln’s Sparrows, a secretive bird which breeds in the boreal fores,t has been in evidence in Northumberland this week. Several SwampSparrows, could be found today (Sept. 27) in field hedgerows, far away from the marshes in which they breed. Both of these sparrows also winter in the continental U.S.

Today we found our first Dark-eyed Junco of the season. This species also breeds in the boreal forest and is a common wintering bird in our area. Many often frequent backyard bird feeders throughout the winter.

Birders continue to scan the beaches at Presqu’ile for shorebirds. The most numerous species last Sunday was Sanderling. This little black, gray and white shorebird can be found scurrying along at the edge of the water searching for insects in the algae collected there.

As well as the Sanderling, there were the smaller Semipalmated Sandpipers, Least Sandpipers, White-rumped Sandpipers, the similar sized but quite differently shaped Semipalmated Plovers, a few Black-belliedPlovers and a single Dunlin.

Owen Point at Presqu’ile is an excellent place to study these species since observers can be quite close to the birds.

On Sept. 15 and 16, all Ontario hawk watches reported good migration numbers. On Sept. 16, Hawk Cliff, on the Lake Erie shore south of St. Thomas, 50,537 hawks were counted. Of these, 49,830 were Broad-winged Hawks. Locally, the numbers of hawks passing were much smaller. On the morning of the 16^th, we observed a couple of groups of Broad-winged Hawks, totaling 42 birds, passing north of Cobourg. Since then, winds have been primarily east and south-east, so the raptor migration has stalled. Look for another large passage of hawks on the next northerly wind.

The one thing constant about migration season is that the birds are always changing. To get a good idea of what is passing through, it in necessary to visit the same location many times.