Dear Luc, IMHO a multinomial mixed model is appropriate for your data. It allows you to model tree species with bird id and period as covariates. Have a look at the vignette of the MCMCglmm package. You will find an example on hornets.
Best regards, Thierry PS R-sig-mixed models is a better list for asking questions on mixed models. ________________________________________ Van: r-help-boun...@r-project.org [r-help-boun...@r-project.org] namens _Luc_ [l.temarve...@nioo.knaw.nl] Verzonden: vrijdag 30 september 2011 14:07 Aan: r-help@r-project.org Onderwerp: [R] How to analyse this type of data...? We have data on habitat use of a bird species (30 radio-tracked individuals). We followed each bird every day for ~45 min for 6 weeks. We recorded a number of things, each minute (a device would beep every minute and we would write down a number of variables). I recorded for example at what kind of tree the bird was foraging on each minute during the observation. In my study area, there are 4 tree species and i want to know if there is a shift in tree species use over the study period (for example, species 1 is used mostly in the beginning, whereas species 3 is only used in the last period of the study while species 4 & 2 are used at the same frequency throughout the study period). In total, tree use is 100% if it always is observed in a tree. Problem is, that the use of tree species is correlated... because if a bird forages in species 1, it automatically does not forage at species 2,3 & 4 at that time. I was wondering how to analyse these data with respect to my question. I can account for multiple observations per bird by adding bird as a random effect in a linear mixed model... but how can i account for the dependence of my tree species? Any advise is welcome... Kind regards Luc -- View this message in context: http://r.789695.n4.nabble.com/How-to-analyse-this-type-of-data-tp3859619p3859619.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
