 
         bird = SKSpriteNode(texture: birdTextureUp)
 
-        bird.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMidY(self.frame))
+        bird.position = CGPoint(x: CGRectGetMidX(self.frame), y: CGRectGetMaxY(self.frame))
+        bird.zPosition = 5      // Always on top
         bird.runAction(flap)
-        bird.zPosition = 4      // Always on top
+
+        bird.physicsBody = SKPhysicsBody(circleOfRadius: bird.size.height / 2)
+        bird.physicsBody?.dynamic = true
 
         self.addChild(bird)
+
+
     }
 }

            bkgr.size.height = self.frame.height

            bkgr.runAction(slideBG)
            bkgr.zPosition = 0

            self.addChild(bkgr)
        }
    }

    func makeFlappingBird() {


import SpriteKit

class GameScene: SKScene, SKPhysicsContactDelegate {

    var bird = SKSpriteNode()
    var bkgr = SKSpriteNode()
    var ground = SKNode()

    override func didMoveToView(view: SKView) {
        self.physicsWorld.contactDelegate = self
        self.physicsWorld.gravity = CGVectorMake(0, -6.0)

        makeBackground()
        makeGround()
        makeFlappingBird()

    }
    
    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
