Around your bird feeder, in the shrubs, or overhead in the sky you can hear birds making sounds all through the year, but during courtship and nesting in the spring oral communications between birds are much more obvious and frequent. Briefly, songs are complex sounds typically used during breeding season to attract mates and defend territories. Calls are simple sounds usually meant to convey a bit of information as to the location of a bird, to keep a flock together, to sound an alarm, etc. – like the sounds flocks of migrating geese make or the chattering around the bird feeder. Songs are only produced by birds classified as songbirds – slightly over 50% of all the birds in the world, but all of them do not produce songs – jays and crows, for example.
It takes a bit of practice to learn to identify avian individuals by their songs or calls and it’s best to learn from someone who knows them. You can go to www.ornithology.com/songscalls.html for links to various sources of bird songs on the web. One caveat; whether you try to learn songs from these sites, from tapes or cds , be aware that birds have accents, just like people. Different populations of songbirds often differ, sometimes considerably, in their songs. Song Sparrows from the east coast may sound different than those on the west. So it’s really best to learn songs in the field in your area.
The late Luis Baptista, a fellow ornithologist and overall nice guy, worked at the Cal Academy of Sciences and studied White-crowned Sparrow songs so intensely that he could recognize individual birds by their song, like we recognize our friends’ voices.
Some philosophers and naturalists would disagree, but or avian friends, unlike us, do not sing for enjoyment. Singing functions in courtship, nesting, and raising young, all necessary for survival of the species – passing genes to the next generation. But it is also dangerous – singing attracts attention and thus competitors and predators. Typically only males sing and typically males are attractively colored. Females rarely sing and are usually dull colored. Singing only occurs in the breeding season. If singing were actually an expression of joy, both males and females would do it all year around. It may be a nice thought that the robin warbling his melodious song is expressing his happiness, but it just isn’t true.
Bird song is partly genetic and partly learned. Experiments have shown that young birds, isolated from their parents, sing a song, but it’s only partly accurate. Young birds have to learn the full song by listening to their parents the spring following the year they were hatched.
Years ago, singing canaries were popular. A radio show in the 1940’s featured dozens of canaries singing with classical records. There was a canary song training record you could use at home to teach your canary to sing: http://www.cas.sc.edu/mcks/Exhibitions/petsInAmerica/canarytrainingrecord.htm . This popularity led unscrupulous pet shop owners to inject both male and female canaries with testosterone, the male hormone that induces singing (and other courtship behavior). After a few weeks, however, the canary’s owner became disappointed at the bird’s cessation of singing as the hormone wore off.