We will use program 2CAPTURE to convert rabbit.cap
to an input file that contains command lines and run it through program
CAPTURE.
Edwards and Eberhardt (1967) reported the results of a live-trapping study on a penned population of 135 cottontail rabbits. The wild cottontails were captured and placed in a 40-acre rabbit-proof enclosure. After allowing 4 days for the rabbits to adjust to their new surroundings, livetrapping was conducted for 18 consecutive days. The raw data are located in a file named rabbit.cap. We are going to use program 2CAPTURE to create an input file named captur.inp. We will use this input file and program CAPTURE to estimate population size, calculate confidence intervals, and perform tests of closure and equal-catchability assumptions.
Download and unzip the latest version of CAPTURE http://137.227.242.23/software.html to your user drive
Copy the rabbit.cap file from CAPTURE directory in S:\COURSES\WLF448\CAPTURE Save it in a folder called Lab10Capture
Use a text editor to view the raw data file named rabbit.cap. Note the format of the data (columns, spacing, binary code) - this is known as X matrix format.
Start program 2CAPTURE by double clicking on 2capture exe. The main menu will appear
In Occasions. This refers to the number of trapping occasions. Enter 18
Under Title enter "Rabbit Data"
Input Type . Select X matrix from the list.
Because data for this example do not include information on capture by trap coordinate (X-Y data), we cannot select Summary statistics.
Click input file button and navigate to where you saved rabbit.cap file. Should be in Lab10Capture folder you created.
To view the input file click View file button (notice the column numbers and range of the data).
Note: this program reads each letter and space as its own column. as an example in this file edward is 6 columns long and w would be in the 3rd column.
You now have to specify file format. This refers to the column numbers and type of data in those columns (see item 6 above). Enter the following: (T15, A3, 3X, 18F1.0). This tells the program: (1) skip to column 15, (2) there is an alpha-numeric identification in columns 15-17, (3) the next 3 columns are blank, (4) capture data consist of 1 character or number, begin in column 21, and continue for 18 columns (corresponding to trap day). Note: parentheses around the file format are required!
Check the box next to Model Selection
Check the box next to Closure Test. This option requests a test of the closure assumption.
Do not input Occasions at this time. Note: this option is used if you want to restrict the analysis to specific trapping occasions, e.g., trap days 1-5 (versus 1-18).
Note: Uniform Density Test option is only available if trapping data include x-y coordinates (i.e., location of traps in a grid).
Estimation. This tells program CAPTURE what analysis options to use.
Select Abundance.
Do not input Occasions (not applicable in this case - we are using all trapping occasions)
Under Estimators.
Select Appropriate (this option tells program CAPTURE to select and use the most appropriate model to estimate abundance). Note: you may select >1 estimator. However, to keep things simple, choose "appropriate" to let the program select the model to use for estimation.
If
everything is okay, under RUN select
CAPTURE.
NOTE: Selecting "execute" will cause 2CAPTURE to create the input file captin. It will continually write over this file each time you run the analysis. So, save this file as something else for future use or later reference if you need.
Use any text editor to view the output. In most cases it will automatically open the output file for you.
Revised: 24 October 2011