Depending upon the number of IVs and DVs, I would think ANOVA or MANOVA would be something to look into... just be sure that the assumptions for the tests are met otherwise you may need to investigate non-parametric tests (e.g. Kruskal-Wallis).
Dear colleague, if you want detect change in density between season you should compare this parameter with non parametric tests as U Mann Whitney or kruskall Wallis (depending on when seasons you would compare). You may try to compare also other variables at population level as biomass. A good textbook for statistical suggestions is Dytham 2011. Sincerely. Corrado
Have you designed a stratified sampling study? If you have more than one habitat type it is better stratify the data: i.e. you should build more data sheets (one for each habitat type). If you want try to send me an example of your data set. ciao
OK. From your dataset you may obtain the averaged density at species level for each period (season). From your raw data you may perform an U Mann Whitney test.
Which are your aims? Questions could be: there are significant differences between species density in spring and winter? (here U test). There are significant differences among seasons around the year? (here a kruskal Wallis test). You may also compare other parameters at community level (richness, diversity, etc.). Ciao. Corrado
If your concern is the seasonal aspect of your avifauna assemblage you have to take into account a couple of issues. Firstly, human concepts of seasons do not quite fit the reality, so be carefully investigate your observations over the entirety of the two years for any obvious natural cycles. Secondly, the more complex analyses demand more assumptions about the data and this is very likely to make the data a reflection of the "assumptions" rather than reflecting "real world occurrences". You may also want to decide if you wish to investigate species variation or variations in assemblages - a slight difference but a difference just the same.