@SuppressWarnings("unchecked")
	public void update(Observable o, Object arg) {
		
		// so wird auf die Position jedes einzelnen Vogels zugegriffen;
		ArrayList<Bird> birds = (ArrayList<Bird>) arg;
		BirdShape birdShape;
		Bird bird;
		
		for (Iterator<Bird> iterator = birds.iterator(); iterator.hasNext();) {
			bird = (Bird) iterator.next();
			xPos = bird.getPosition().getX();
			yPos = bird.getPosition().getY();
			birdShape = bird.getBirdShape();
			birdShape.setPoint(xPos, yPos);
			birdShape.setOrientation(bird.getVelocity().getNormalizedVector());
		}
		
		// erneuere den Raubvogel:
		bird = preyBird;
		xPos = bird.getPosition().getX();
		yPos = bird.getPosition().getY();
		birdShape = bird.getBirdShape();
		birdShape.setPoint(xPos, yPos);
		birdShape.setOrientation(bird.getVelocity().getNormalizedVector());
		birdPanel.repaint();
		
		
	}