Do you want to describe the six song types? Do you want to describe within or among-individual variation?

the first step is to define what you want to demonstrate/show: their behavioral function/meaning ? their stability/stereotypy for species recognition ? their specificity versus other similar species ? their possible use for automatic species recognition ?

A basic spectrographic analysis might be enough for most of these cases, but you need a suitable sample size. You need N individuals (or N recordings of different individuals, maybe with some degree of individual replication).

According to the shapes you see on the spectrogram, and also according to your listening of the sounds, you then need to identify some measuring points that enable you to characterize the vocalizations and analyze them statistically.

that's the basic strategy, then you need to tune it according to your research goals.

Gianni

The works of Kazuo Okanoya and Ofer Tchernichovsky can be a great start to refine your ideas. All the best. Marco

You might contact Amanda G. Sandler, Andrews University. She is doing graduate work in that area and has a lot of contacts and information. Shandelle Henson

you need receive sonogramms or spectrograms pf songs and then do analyse of their sturcuture. If this species has typological structure of song you will do it very easy. If this species have not typological struycture and have high variability of song it is better to analyse soem elements of song  but not full song.

Thanks a lot to all dear scientists for your precious valuable suggestions ...Please also suggest me a window based software  for HMM analysis.

you can use any software which give you picture of change of frequency in time. Any program ( software)  for sound analysis even for musicians and singers not specially for for bird sounds. A lot of programs. 

It is easy now. 30 years before it took a lot of time and we used other methods for receiving of this picture.

Try Ravenlite from Cornell

http://store.birds.cornell.edu/Raven_Lite_p/ravenlite.htm