How to move Sprite in Pygame

im trying to get my image (bird) to move up and down on the screen but i cant figure out how to do it here is what i tried im sure its way off but im trying to figure it out if anyone can help that would be great!

import pygame
import os

screen = pygame.display.set_mode((640, 400))

running = 1

while running:
    event = pygame.event.poll()
    if event.type == pygame.QUIT:
        running = 0
    screen.fill([255, 255, 255])
    clock = pygame.time.Clock()
    clock.tick(0.5)
    pygame.display.flip()

    bird = pygame.image.load(os.path.join('C:\Python27', 'player.png'))
    screen.blit( bird, ( 0, 0 ) )

    pygame.display.update()

class game(object):
    def move(self, x, y):
        self.player.center[0] += x
        self.player.center[1] += y


    if event.key == K_UP:
        player.move(0,5)
    if event.key == K_DOWN:
        player.move(0,-5)

game()

im trying to get it to move down on the down button press and up on the UP key press

As stated by ecline6, bird is the least of your worries at this point.

Consider reading this book..

For now, First let's clean up your code...

import pygame
import os

# let's address the class a little later..

pygame.init()
screen = pygame.display.set_mode((640, 400))
# you only need to call the following once,so pull them out of the  while loop.
bird = pygame.image.load(os.path.join('C:\Python27', 'player.png'))
clock = pygame.time.Clock()

running = True
while running:
    event = pygame.event.poll()
    if event.type == pygame.QUIT:
        running = False

    screen.fill((255, 255, 255)) # fill the screen
    screen.blit(bird, (0, 0))    # then blit the bird

    pygame.display.update() # Just do one thing, update/flip.

    clock.tick(40) # This call will regulate your FPS (to be 40 or less)

Now the reason that your "bird" is not moving is:
When you blit the image, ie: screen.blit(bird, (0, 0)),
The (0,0) is constant, so it won't move.

Here's the final code, with the output you want (try it) and read the comments:

import pygame
import os

# it is better to have an extra variable, than an extremely long line.
img_path = os.path.join('C:\Python27', 'player.png')

class Bird(object):  # represents the bird, not the game
    def __init__(self):
        """ The constructor of the class """
        self.image = pygame.image.load(img_path)
        # the bird's position
        self.x = 0
        self.y = 0

    def handle_keys(self):
        """ Handles Keys """
        key = pygame.key.get_pressed()
        dist = 1 # distance moved in 1 frame, try changing it to 5
        if key[pygame.K_DOWN]: # down key
            self.y += dist # move down
        elif key[pygame.K_UP]: # up key
            self.y -= dist # move up
        if key[pygame.K_RIGHT]: # right key
            self.x += dist # move right
        elif key[pygame.K_LEFT]: # left key
            self.x -= dist # move left

    def draw(self, surface):
        """ Draw on surface """
        # blit yourself at your current position
        surface.blit(self.image, (self.x, self.y))


pygame.init()
screen = pygame.display.set_mode((640, 400))

bird = Bird() # create an instance
clock = pygame.time.Clock()

running = True
while running:
    # handle every event since the last frame.
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit() # quit the screen
            running = False

    bird.handle_keys() # handle the keys

    screen.fill((255,255,255)) # fill the screen with white
    bird.draw(screen) # draw the bird to the screen
    pygame.display.update() # update the screen

    clock.tick(40)