"Sweet-sweet-sweet; I'm so sweet." The lovely phrase came to us from the treetops off to our left. "Sweet-sweet-sweet; I'm so sweet;" the song tumbled out of a stand of willows at the edge of the pond. The sun was out; the air was warm; and the birds were singing. For birders, winter was officially over; the warblers were back.

Our eyes followed our ears and we quickly saw the songster. Our first impression was that the bird was entirely yellow. After a moment's further inspection, we saw the chestnut streaks on the bird's breast. The back and wings had an olive tone that tended slightly more yellow than green. A black eye in a bright yellow face stared back at us, as the bird continued its song.

To me, yellow warblers (Setophaga petechia) are the epitome of the warbler family. Most warblers have some yellow, and most sing beautiful songs to court mates and defend their territory. Yellow warblers highlight both traits and have the added benefit of being relatively easy to see. That "sweet-sweet-sweet" song was loud and clear and sung from the tops of trees, where the abundant bright yellow birds were readily picked out.

Yellow warblers are one of the most widespread neo-tropical migratory birds in North America. Each spring, the birds head north from their wintering grounds in Central and South America. In the eastern part of the hemisphere, yellow warblers settle on breeding grounds just north of the Gulf Coast states and extend into every Canadian Maritime province.

They are found in every Chesapeake state. In the western half of the hemisphere, the birds nest in areas ranging from the northern Mexican states all the way up to Alaska and the top tier of Canadian provinces.

One of the subspecies of yellow warblers (there are more than 40) is the northernmost breeding warbler in North America. As a species, the birds cover a huge amount of geography, but their nesting areas all have something in common: They are areas with thickets along streams, ponds and wetlands.

Yellow warblers are among the first migrants to arrive in North America annually. The birds that come to the eastern United States make the arduous nonstop flight over the Gulf of Mexico, arriving in their breeding grounds starting in early April.

Regardless of their destination, yellow warblers represent the first wave of avian migrants each year; they will be followed by buntings, orioles and tanagers in the next few weeks.

There are more than 50 warblers in North America and they come in almost every color. But yellow is the one hue most strongly associated with warblers. Some have yellow streaks and others yellow rumps or cheeks, but most of them have some yellow that is a characteristic field mark. Yellow warblers have earned the right to bear that color as their name. After their first year, both males and females are predominately yellow, and they are the only wood warbler with yellow tail spots. The tiny, coal black eye in the middle of the all-yellow face just emphasizes the surrounding hue.

As evidenced by his chestnut breast stripes, the bird that first captured our attention was a male. Females don't have those handsome breast markings. Females may be a bit more drab, but they are still unmistakably yellow birds.

Females make the nests, lining them with every imaginable soft item, ranging from deer hair and feathers to the puffy seeds of dandelions.

Brown cowbirds frequently parasitize these nests by laying eggs in them and waiting for the yellow warbler to incubate and feed the resultant chick. The hosts, though, fight back. The female yellow warbler may build a new nest directly on top of the old one, smothering both her clutch of eggs and the cowbird's in an effort to start over.

Yellow warblers love willows and the other trees and shrubs that inhabit damp areas along streams and wetlands. These birds eat a diet almost exclusively of insects and similar species like spiders. They forage among the leaves, grabbing caterpillars, leafhoppers, and beetles. Yellow warblers will also take short flights off the branches to nab midges and even wasps on the wing. Because of their insect diet, yellows are unlikely to be seen at backyard bird feeders.

We didn't have to go far to find them. A rough, dirt pull-off from the road gave us a safe place to park and easy access to these lively birds.

A month ago, gray moods matched gray skies as winter's last gasp felt endless. Today, thanks to a bright warbler with an irrepressible song, that all seems like ancient history. Spring was here and it was "sweet, sweet, sweet."