If you want to know spring is here, don't look first for the tree leaves or the woodland wildflowers. Don't look for baby birds or wait for balmy breezes.

If you want to know spring is here, don't look first for the tree leaves or the woodland wildflowers. Don't look for baby birds or wait for balmy breezes.

Instead, close your eyes and open your ears. Listen for the frogs, and listen for the birds.

Winter has worn thin this year, and honestly, I'm tired of looking at bare branches that are part of the dull browns, tans and grays. But rest assured, spring is creeping up on us, even if it seems to be at a snail's pace.

Here at Hogback Ridge Preserve in Sunbury, visible signs of spring remain elusive. During a walk, I found a few wildflowers trying to emerge from the leaf litter, but they are barely out of the ground, and there are buds on the trees but no leaves.

No, it is still rather taupe and gray in the natural world. But -- and here is the good news -- the abundance of sounds being made by birds and frogs right now makes up for the lack of color.

The frogs are singing their little hearts out, especially on warmish days. Even when winter kept its grip on us, they were interpreting clues from nature that told them it was time to travel to vernal (springtime) wetlands and begin breeding. The sounds can be deafening when hundreds of little frogs are singing to attract mates all at the same time.

At Gallant Woods Preserve in Delaware, there are more than 20 acres of wetlands and woodland vernal pools -- and they are teeming with frogs. During a recent visit, the din greeted me before I even entered the park and grew steadily louder as I drove deeper in. Especially active was a small wetland encircled by the Gateway Trail (grab a trail map from the kiosk).

Spring peepers were chirping away; they sound like a string of jingle bells when they are singing en masse. And the chorus frogs chimed in with their song, which sounds like dozens of fingers running along the teeth of dozens of combs.

The frogs were busy at Liberty Township's Deer Haven Preserve, too, and the wetlands behind the lodge were brimming with sound. A few years ago, I would not have frogs that close to the lodge, but the wetlands that Preservation Parks developed in the park are starting to mature, and all manner of wildlife are making themselves at home.

One resident there is the red-winged blackbird -- one of my favorites. Its song is distinctive; experts say it sounds like the bird is saying "conk-la-ree," with the final syllable drawn out and a little raspy. The red-winged blackbird hangs out near the cattails, in other wetland areas, and in the dry meadows as well.

During my walk at Deer Haven, I saw a half-dozen of them flying around, singing and showing bright flashes of red and yellow on their wings.

Overhead, a few tree swallows moved in and out of their nest boxes, which are set up in grid. Tree swallows are agile aerialists; as I watched, they kept up their twittery, fluttery song even as they flew -- no doubt seeking flying insects to nab mid-flight.

Closer to the bird-feeders and the woods, the familiar song of the northern cardinal caught my ear. Easily recognizable by even the most novice birder, its bright red seems to be the only color in the woods during the winter. Its song is easy to identify as well; one common pattern sounds like "purdy, purdy, purdy, purdy ... whoit, whoit, whoit, whoit."

The American goldfinches have resumed their springtime song as well. A year-round resident, the (male) goldfinch fades to a dull greenish khaki color in the winter, and limits its voice to a few calls. But in the spring, its very melodic, rambling and canary-like song returns, as does its brilliant yellow plumage. Signs of spring, for sure!

Spring is returning, and visitors to the parks can participate in upcoming programs that will showcase the season with a feast for their eyes and their ears.

•Wildflower Ways: 2 p.m. Saturday, April 26, Shale Hollow Preserve, 6320 Artesian Run in Delaware. Join us on a leisurely hike to learn the names and folklore of many of the spring wildflowers. This program is for ages 7 and older.

•Fantastic Frogs: 6 p.m. Saturday, May 3, Gallant Woods Preserve, 2151 Buttermilk Hill Road. The spring night air is full of croaks and trills, and we'll jump right into the wetlands to learn about the frogs that are making these noises. This program is for all ages; boots are recommended.

Sue Hagan is marketing and communications manager for Preservation Parks of Delaware County.