"Sweet-sweet-sweet, I'm so sweet!" "Wichitywichity-wichity!" "Zee-zee-zee, zoo-zee!" Is it the bird clock on the wall? No, it's spring! Days are getting longer and warmer, flowers and trees are blooming, and birds are singing their hearts out -driving us crazy as we try to remember which bird is singing which song.

The arrival of spring means the return of songbirds that fill the outdoors with a chorus of sound. Each year as the birds begin their serenades, many birders, including me, struggle to remember those bird songs we thought we had learned the previous spring.

Bird songs, however, are not there just to puzzle birders. How and why the songs are sung play a vital role in a bird's life. Songs define a territory and announce to prospective mates the availability of a nesting site and a partner. Considering where songbirds live, how small they are, and the visual barriers in their habitats, like leaves and trees, songs are the most effective way for birds to communicate.

Males make up the majority of the chorus in the bird world, but there are a few species like the cardinal, where the females sing, too. The males sit up on a perch declaring their domain and serenading prospective mates. While each species has its own primary song, there may be regional dialects as well as subtle individual differences.

Birds do not have vocal chords like humans, so how do they manage those intricate ditties? They produce their songs by controlling the frequency of vibrations made by the membranes in the syrinx, or voice box. Birds with more membranes, such as crows or mockingbirds, produce a greater variety of sounds, while those with less, like the pigeon, produce fewer sounds.

In addition to their primary songs, birds have a number of other vocalizations. Subsongs are random variations interspersed with a few notes from the primary song, while mute songs are a whispered version of the primary song. Whistles, calls and chips indicate alarm or communicate messages to others in the flock. For some species, the songs they sing are inherited, but for others they learn the song of their species by listening to other birds.

There are over 950 species of birds in North America, all with their own repertoire of songs and calls. While we may not remember who sings "tcher, tcher, tcher, tcher" this spring, the birds have it all figured out.

Nancy Biegel
Recreation Assistant, ESNWR