bird_button=new Image(102,38); bird_button2=new Image(102,38);
bird_button.src="images/bird_button1.gif"; bird_button2.src="images/bird_button2.gif"; 
walks_button=new Image(102,38); walks_button2=new Image(102,38);
walks_button.src="images/walks_button3.gif"; walks_button2.src="images/walks_button4.gif";