With bird migration, no two springs are ever the same. But this year has been highly unusual.

Migration started off fairly typically, with early migrants like Baltimore orioles and yellow-rumped warblers appearing in good numbers by early May.

But then things ground to a screeching halt.

For the next two weeks, bird watchers in the metro area began scratching their heads over the scarcity of spring migrants.

It wasn't only the small, colorful warblers that were missing, but also big, showy birds like scarlet tanagers. And, while we're at it, where were the Eastern towhees and the several vireos? Some birders began to speculate about what might be causing our nearly migrant-free spring.

Suddenly, things changed.

Stationary weather fronts that had trapped migratory birds in the South shifted, and a southerly wind began blowing the migrants northward. By mid-May, warblers and tanagers and other missing species started showing up in the Twin Cities in such numbers that they seemed to be making up for lost time.

Local nature centers, natural areas and riverside parks were popping with migrants, even in the rainy, stormy weather. And backyard bird watchers began seeing warblers and scarlet tanagers at their feeders, an unusual sight because these insect-eating birds tend to stay high up in trees.

Those birds were looking for quick calories to replenish their body fat after long flights, and our cold, wet spring was tough on them.

This influx of migratory birds should continue for the next week or so, while they make their way to their breeding grounds in northern Minnesota and Canada.

Look for them in parks and open spaces along lakes and streams, as well as woodlands and marsh edges. To see the brilliant red coat and black wings of the scarlet tanager, look up into the trees. To get a glimpse of warblers, watch for rapidly moving small birds in trees and shrubs, then train your binoculars on them to get a close look at their beautiful and variously colored plumage.

You might be lucky enough to catch the Blackburnian warbler, with its orange throat, or my personal favorite, the black-throated green warbler, with its green back and black chin.

Once they're gone, we can celebrate this wild spring, with its colorful and condensed migration and the fact that warblers and tanagers continue to make their way from the tropics to northern nesting areas. And we're lucky enough to be smack dab in the middle of it.

St. Paul resident Val Cunningham, who volunteers with the St. Paul Audubon Society, can be reached at valwrites@comcast.net.