Full Jolly-Seber

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The following analysis is carried out if Open methods: Full Jolly-Seber is selected from the drop-down menu.

 

openfulldropdown

 

 

If full individual tagging data are input, then Simply Tagging calculates and tabulates the recapture data according to the date of initial capture (or mark) and the date on which the animal was last captured. The columns are then summed to give the total number of animals released and subsequently recaptured (Ri). Alternatively, if batch tagging has been undertaken then the user will enter this in the summary table. This recapture table can be viewed by clicking on the Jolly Summary tab.

 

Once an analysis is initiated by selecting one of the options in the Open methods drop-down, another table is calculated giving the total number of animals recaptured on day i bearing marks of day i-1 or earlier; this is done by adding each row in the Jolly Summary table from left to right and entering the accumulated totals. The number marked before time i which are not caught in the ith sample, but are caught subsequently (Zi), is found by adding all but the top entry in each column. This table is viewed by clicking on the Recaptures tab.

 

Then:

The estimate of the total number of marked animals at risk in the population on the sampling day i is made.
The proportion of marked animals in the population at the moment of capture on day i is found.
The total population is estimated for each day.
The probability that an animal alive at the moment of release of the ith sample will survive till the time of capture of  the i + 1th sample is found. Survival rate estimates slightly over one may arise from sampling effects, but rates greatly above this indicate a major error! Frequently it will be found that the marks of one occasion have been lost or were not recognised. This survival rate may be converted to a loss rate (the effect of death and emigration):
The number of new animals joining the population in the interval between the ith and i + 1th samples and alive at time i + 1 is calculated.
Standard errors (the square roots of the variances) are calculated.

 

The results of the above calculations are viewed by clicking on the Jolly-Seber results tab. The parameter estimates are arranged in columns with the rows representing each of the samples. A plot of the population size through time (at the times when samples were taken) is obtained by clicking on the Plot estimates tab.