Appending text files using buffered type writer java

I'm trying to store data that is being inputted by a user and store it in a text file to be manipulated later on, I'm having problems with it keep on overwriting the first lines on data code below:

public void AddDataToFile(int i)

{
    BufferedWriter writer = null;
    try {

        writer = new BufferedWriter(new FileWriter("./Cat Info.txt"));

        Cat catCurrent;
        catCurrent = catPenArray [i];            
        writer.append("Pen Number " + (i + 1));
        writer.newLine();
        writer.write("Cat Name " + catCurrent.CatName);
        writer.newLine();
        writer.write("Cat Gender " + catCurrent.Gender);
        writer.newLine();
        writer.write("Chip Number " + catCurrent.ChipNumber);
        writer.newLine();
        writer.write("Arival Date " + catCurrent.ArrivalDate);
        writer.newLine();
        writer.write("Departure Date " + catCurrent.DepartureDate);
        writer.newLine();
        writer.write("How often fed " + catCurrent.HowOftenFed);
        writer.newLine();
        writer.write("Type Of food " + catCurrent.Food);
        writer.newLine();
    } catch (IOException e) {
        System.err.println(e);
    } finally {
        if (writer != null) {
            try {
                writer.close();
            } catch (IOException e) {
                System.err.println(e);
            }
        }
    }
}