Classic learning (memory-based)
Young birds listen to and memorize the songs of adults. They can distinguish their song from other species song and they are predisposed to learn their own species song patterns. The young possess a rough template of their song. They memorize those songs that match the template.
The young of some species learn from their father, practicing his song until they master it. Some learn from neighboring adults.
There is a window of time when they are sensitive for memorizing the song. It usually starts around fledging when adults of the species are singing. The length of the sensitive period varies greatly by species.
In the practice phase they produce sounds, listen to the results and compare and match their vocalizations to the memorized template. First they produce soft, rambling sounds called subsong. Subsong gradually becomes more like the species adult song but is still variable. During this phase it is called plastic song. The young bird rehearses until his song develops into the typical song of adults, called crystallized song. For some species crystallization occurs the following spring. Some earlier while they are still a juvenile.
The four stages in the classic learning model are 1) memorization, 2) subsong, 3) plastic song and 4) crystallization
(Marler 1981) .
Marler, P. (1981) Birdsong: the acquisition of a learned motor skill. Trends Neurosci, 4:88-94.
Later Selection
Selects songs closest to neighbors. Rest dropped.
Some learn as juveniles. Some as juveniles and as adults, Some change in production, learn large repertoire and sing subset of those. Memorize more songs than use. Field sparrow, white-crowned sparrow
Learning as adults/changing song as adults
Indigo buntings, starlings
Action-based
Memorize more elements than use. Drop elements
Selection/recombining elements taking place at production
swamp sparrow
Improvise and invent
Birds that have a large repertoire (brown thrasher 1000+ songs and gray catbird) improvise and invent songs. They learn songs throughout their lives. They sing a long series of variable notes not in a fixed sequence. The mechanism controlling improvisation is not understood. For brown thrashers it has been shown that exposure to adult song during and after fledging doesn’t seem necessary for full song to develop. It seems best when raising these birds to expose them to the variety of species that they would normally hear in the wild.
Northern mockingbirds are often grouped with brown thrashers and gray catbirds because they have a large repertoire (100-200 songs) and their song is not a fixed sequence of elements. However, mockingbirds do appear to learn from adults as they don’t develop good song without exposure when young. They are good mimics and can learn the songs of other species and can imitate natural and man made sounds as well.
Innate song
A few birds, suboscines, do not learn their song. It is innate. Alder and Willow flycatchers, brown woodcreeper and the eastern phoebe are in this group. They have simpler syringes and lack the specialized birdsong regions in the brains of the oscines (Kroodsma 2005) .
- Male song sparrows cycle through their songs in AAAA, BBBB … repeating one type in a bout before switching Bird Song p186
- Song sparrows who share songs live longer and keep their territories longer (Kroodsma p66)
- Repertoire size influences reproductive success (Bird Song p 186)
- Difference in song in various areas is due to structure above element level (Searcy et al, 2003 from Bird Song p249)
- Accurate production of local song a cue to male quality (Searcy et al. 2002 from Bird Song p249)
- Sedentary populations share more songs than migratory populations (Peters et al 2000 from Bird Song p244)